Universal oscilloscopes of group C1. Purpose and general information

If you ask a professional electronics adjuster or radio engineer: “What is the most important device in your workplace?” The answer will be clear: “Of course, an oscilloscope!” And indeed it is.

Of course, it is impossible to do without a multimeter. Measure the voltage in control points circuits, measure resistance and current, “ring” a diode or check a transistor - all this is important and necessary.

But when it comes to adjusting and tuning any electronic device from a simple TV to a multi-channel transmitter orbital station, then it’s impossible to do without an oscilloscope.

The oscilloscope is designed for visual observation and control periodic signals any shape: sinusoidal, rectangular and triangular. Thanks to its wide sweep range, it allows the pulse to be sweeped so that even nanosecond intervals can be monitored. For example, measure the rise time of a pulse, and in digital equipment this is a very important parameter.

An oscilloscope is a kind of television that displays electrical signals.

How does an oscilloscope work?

To understand how an oscilloscope works, consider a block diagram of an averaged device. Almost all oscilloscopes are designed this way.

Only two are not shown in the diagram. power supply: a high voltage source that is used to generate high voltage entering the CRT ( cathode-ray tube) and low-voltage, ensuring the operation of all components of the device. And there is no built-in calibrator, which is used to configure the oscilloscope and prepare it for operation.

The signal under study is applied to the input " Y" channel of vertical deflection and goes to the attenuator, which is a multi-position switch that regulates sensitivity. Its scale is calibrated in V / cm or V / division. This refers to one division of the coordinate grid applied to the CRT screen. The values ​​themselves are also printed there: 0, 1 V, 10 V, 100 V. If the amplitude of the signal under study is unknown, we set the minimum sensitivity, for example, 100 volts per division. Then even a signal with an amplitude of 300 volts will not damage the device.

Any oscilloscope includes 1:10 and 1:100 dividers; they are cylindrical or rectangular attachments with connectors on both sides. Performs the same functions as an attenuator. In addition, when working with short pulses, they compensate for the capacitance of the coaxial cable. This is what the external divider from the S1-94 oscilloscope looks like. As you can see, its division ratio is 1:10.

Thanks to an external divider, it is possible to expand the capabilities of the device, since when using it, it becomes possible to study electrical signals with an amplitude of hundreds of volts.

From the output of the input divider the signal goes to preamplifier. Here it branches and enters delay line and to the timing switch. The delay line is designed to compensate for the response time of the scan generator with the arrival of the signal under study to the vertical deflection amplifier. The final amplifier generates the voltage supplied to the plates" Y" and ensures vertical beam deflection.

Scan generator generates a sawtooth voltage, which is applied to the horizontal deflection amplifier and to the plates " X" CRT and provides horizontal beam deflection. It has a switch graduated as time per division ("Time/div"), and a sweep time scale in seconds (s), milliseconds (ms) and microseconds (μs).

The synchronization device ensures that the scan generator starts running simultaneously with the appearance of the signal at the starting point of the screen. As a result, we see an image of the pulse on the oscilloscope screen unfolded in time. The timing switch has the following positions:

Synchronization from the signal under study.

Synchronization from the network.

Synchronization from an external source.

The first option is the most convenient and is used most often.

Oscilloscope S1-94.

In addition to complex and expensive models of oscilloscopes that are used in the development of electronic equipment, our industry has launched the production of a small-sized oscilloscope C1-94 specifically for radio amateurs. Despite its low cost, it has proven itself in operation and has all the functions of an expensive and serious device.

Unlike its more sophisticated counterparts, the S1-94 oscilloscope is quite small in size and easy to use. Let's look at its controls. Here is the front panel of the S1-94 oscilloscope.

To the right of the screen from top to bottom.

Knob: "Focus".

"Brightness" knob.

These controls can be used to adjust the focus of the beam on the screen, as well as its brightness. In order to extend the service life of the CRT, it is advisable to set the brightness to a minimum, but so that the readings are clearly visible.

• Net" Device power button.

  



Mode button " Zhdushch-Aut».



This is a button for selecting standby and automatic sweep modes. When operating in standby mode, the sweep is triggered and synchronized by the signal being studied. In automatic mode, the sweep starts without a signal. To study a signal, the standby mode for starting a scan is often used.

This button selects the polarity of the trigger pulse. You can choose to trigger from a pulse of positive or negative polarity.



Synchronization button " Internal-External».



Typically, internal clocking is used, since using an external clock signal requires a separate source of this external signal. It is clear that in the vast majority of cases this is not necessary in a home workshop. The external clock input on the front panel of the oscilloscope looks like this.

Button for selecting “Open” and “Closed” input.



Everything is clear here. If you intend to study a signal with a constant component, then select “Variable and constant”. This mode is called “Open”, since a signal containing a constant component or low frequencies in its spectrum is supplied to the vertical deflection channel.

At the same time, it is worth considering that when the signal is displayed on the screen, it will go up, since the level of the constant component will be added to the amplitude of the variable component. In most cases it is better to choose a "closed" entrance ( ~ ). In this case, the constant component of the electrical signal will be cut off and will not be displayed on the screen.

The “housing” terminal serves to ground the device body. This is done for security reasons. In a home workshop, sometimes it is not possible to ground the device body. Therefore, you have to work without grounding. It is important to remember that when the oscilloscope is turned on, there may be a voltage potential on the body. When you touch the body, it may “pull”. It is especially dangerous to touch the oscilloscope body with one hand and radiators or other operating electrical appliances with the other hand. In this case, the dangerous potential from the body will pass through your body (“arm” - “hand”) and you will receive an electric shock! Therefore, when operating the oscilloscope without grounding, it is advisable not to touch the metal body parts. This rule is also true for other electrical appliances with a metal body.

In the center of the front panel there is a “sweep” switch - Time/div. It is this switch that controls the operation of the scan generator.



Just below is the input divider (attenuator) switch - V/div. As already mentioned, when studying a signal with an unknown amplitude, it is necessary to set the maximum possible value of V/div. So for the S1-94 oscilloscope you need to set the switch to position 5 ( 5V/div.). In this case, one cell on the screen grid will be equal to 5 volts. If you connect a divider with a division ratio of 1 to 10 (1: 10) to the “Y” input of the oscilloscope, then one cell will be equal to 50 volts (5V/div * 10 = 50V/div).

Also on the oscilloscope panel are:

Currently, with the development of digital technology, digital oscilloscopes have become widely used. Essentially it is a hybrid of analog and digital technology. The attitude towards them is ambiguous, like a meat grinder with a processor or a coffee grinder with a display.

Analog equipment has always been reliable and easy to use. In addition, it was easy to repair. A digital oscilloscope costs an order of magnitude more and is very difficult to repair. Of course there are many advantages. If analog signal using an ADC (analog-to-digital converter) to convert it into digital form, then you can do whatever you want with it. It can be recorded in memory and displayed at any time for comparison with another signal, added in phase and antiphase with other signals. Of course, analog technology is good, but digital electronics future.

The oscilloscope is considered one of the critical devices, which is used in electrical engineering. With its help, measurements are taken of various important parameters any devices. Many devices operate as components of various equipment that require precision in operation. The oscilloscope, with the help of which the measurement work was carried out, allows us to prevent the use of low-quality elements in various electronic circuits Oh.

Why do you need an oscilloscope: application and types

Job of this device is based on testing various electronic circuits. An oscilloscope is capable of displaying the shapes of any electrical signals, while displaying changes in voltage over time, according to which you can find out what is happening in a working circuit.

The operating principle inherent in all oscilloscopes is the same. But these devices differ in the way the signal is processed.

Main types of oscilloscopes:

• Analog;
• Digital.

With the advent of these devices, everything was analog. Paying attention to the name of the device, you can understand that analog is the method of displaying images on the screen. To do this, analog oscilloscopes use a cathode ray tube, where the voltage applied to the axes (X and Y) moves a dot across the screen.

The horizontal line indicates the signal travel time, and the vertical line is proportional to the input signal. The work is carried out as follows. Boosted signal, passes through the electrodes of the device, while according to analog technology, electrons are deflected along the Y axis.

Note! The measurements taken by this device cannot be obtained using, for example, a multimeter.

The operation of an electronic device is carried out by converting the signal into a digital format, after which the data is processed in digital form. It is worth noting that digital oscilloscopes can come in various modifications. With digital phosphor, stroboscopic and combined.

There are many different modifications of oscilloscopes: 65 a, N313, 1 112 a, f 4372.

Oscilloscope s 1 49: characteristics

This device allows you to observe and study forms of processes (electrical). The frequency range varies from 0 to 5 MHz. Each device has different characteristics from each other.

Characteristics from 1 49:

• Single beam oscilloscope;
• The voltages that the device measures are from 20 mV to 200 V;
• Time intervals from 8 µs to 0.5 seconds;
• Transmission (bandwidth) from 0 to 5.5 MHz;
• Time interval error up to 10%;
• Signal amplitude error up to 10%;
• Beam width 0.6 mm;
• Operating voltage 220 Volts at 50 Hz and 115 Volts at 400 Hz;
• Device power 38 VA;
• Screen 36 by 60 mm;
• Operating air temperature from – 30 to + 50 0 C.

The Y channel parameters include the following. Its sensitivity ranges from 10 to 20 V/div. The channel resistance at the input reaches 1 mOhm. The input capacitance is 50 picofarads.

The X channel parameters include: Minimum sweep duration is 0.2 µs. Maximum duration 10 µs. External synchronization signals from 0.5 to 30 V. External synchronization frequencies from 1 Hz to 5 MHz. Input resistance 1 mOhm.

Note! Different kinds oscilloscopes have an insignificant content of precious metals.

Channel Z and its main parameters. Channel frequencies from 30 Hz to 1 MHz. Input voltage from 10 to 60 Volts. Input resistance 1 mOhm. Each device is accompanied by a schematic diagram.

C 1 49: operating instructions for beginners

On the oscilloscope body there are a large number of switches and controls. In order not to get confused in all of them, you should study the purpose of each.

Device controls:

• Toggle switch to turn on;
• Focus and brightness controls;
• Rotary knob – Y gain;
• Gain switch;
• Scan adjustment;
• Toggle switch – internal and external;
• Level adjustment;
• Stability control knob.

The device is turned on using the toggle switch (network), which is located on the right side of the screen.

The thickness of the beam on the screen can be changed using the regulator marked (focus). The brightness of the screen is adjusted using the knob (brightness).

Note! Screen brightness is adjusted depending on external lighting conditions.

The vertical beam span is adjusted using the rotary knob (Y gain). The sensitivity level is adjusted depending on the signal strength.

The device is equipped with a special connector (bayonet mount) for a special adapter.

In order to select the desired range of the measured voltage, rotate the rotary knob labeled (gain).

It is necessary to shift the starting point of the pulse horizontally if it is outside the measurement scale. To do this, use a handle (reamer).

To use external generators, use a special connector marked (input X).

The selection of the source from which the scan will be performed is carried out using a toggle switch (internal and external).

To change the sensitivity of the signal, use a regulator marked (level).

The signal is synchronized with the sweep by adjusting the handle (stability).

How to use an oscilloscope: taking measurements

Before starting measurement work, you should connect the oscilloscope to the network. After the connection is made, using the toggle switch marked (network), we supply power to the device.

Work order:

• Warming up the oscilloscope;
• Functionality check;
• Measuring work.

After connecting the device to the network, you need to “warm it up”. This is done to stabilize all parameters for all components of the device. The device warms up within five minutes.

Then, using the controls marked (Y gain and scan), you need to position the measuring beam in the center of the device screen.

Note! Calibration using this method is carried out provided that the regulator (duration) is on the one millisecond mark.

Signal measurement is carried out by adjusting the handles (duration and gain), setting them to the extreme left position.

Gain increases the measuring range until the most audible signals appear on the screen. The duration determines the frequency of the signal.

After all the controls are set and there is a stable signal on the screen, the voltage and frequency are calculated.

This article assumes the use of the factory circuit diagram of the device.

Many specialists, and especially radio amateurs, are well aware of the S1-94 oscilloscope (Fig. 1). The oscilloscope, with its quite good technical specifications, has very small dimensions and weight, as well as a relatively low cost. Thanks to this, the model immediately gained popularity among specialists involved in mobile repair of various electronic equipment, which does not require a very wide frequency band of input signals and the presence of two channels for simultaneous measurements. Currently, a fairly large number of such oscilloscopes are in use.

In this regard, this article is intended for specialists who have a need to repair and configure the S1-94 oscilloscope. The oscilloscope has a block diagram that is typical for devices of this class (Fig. 2). It contains a vertical deflection channel (VDC), a horizontal deflection channel (HDC), a calibrator, an electron beam indicator with a high-voltage power supply and a low-voltage power supply.

The KVO consists of a switchable input divider, preamp, delay line and final amplifier. It is designed to amplify a signal in the frequency range 0...10 MHz to the level necessary to obtain a given vertical deviation coefficient (10 mV/div... 5 V/div in steps of 1-2-5), with minimal amplitude frequency and phase-frequency distortions.

The KGO includes a synchronization amplifier, a synchronization flip-flop, a trigger circuit, a sweep generator, a blocking circuit, and a sweep amplifier. It is designed to provide linear beam deflection with a specified sweep ratio from 0.1 μs/div to 50 ms/div in steps of 1-2-5.

The calibrator produces a signal to calibrate the device in amplitude and time.

The cathode ray indicator assembly consists of a cathode ray tube (CRT), a CRT power circuit, and a backlight circuit. The low-voltage source is designed to power all functional devices with voltages of +24 V and ±12 V.
Let's look at the operation of an oscilloscope at the circuit diagram level.

The signal under study through the input connector Ш1 and push-button switch B1-1 (“Open/Closed input”) is supplied to the input switchable divider on elements R3...R6, R11, C2, C4... C8. The input divider circuit ensures a constant input resistance regardless of the position of the vertical sensitivity switch B1 (“V/DIV.”). Divider capacitors provide frequency compensation for the divider over the entire frequency band.

From the output of the divider, the signal under study is fed to the input of the KVO pre-amplifier (block U1). A source follower for an alternating input signal is assembled on field-effect transistor T1-U1. By DC this stage provides symmetry of the operating mode for subsequent amplifier stages. The divider on resistors R1-Y1, Y5-U1 provides an input resistance of the amplifier equal to 1 MOhm. Diode D1-U1 and zener diode D2-U1 provide input overload protection.

Rice. 1. Oscilloscope S1-94 (a - front view, b - rear view)

The two-stage pre-amplifier is made on transistors T2-U1...T5-U1 with a common negative feedback(OOS) through R19-Y1, R20-Y1, R2-Y1, R3-Y1, S2-U1, Rl, C1, which allows you to obtain an amplifier with the required bandwidth, which practically does not change with a stepwise change in the cascade gain of two and Five times. The gain is changed by changing the resistance between the emitters of transistors UT2-U1, VT3-U1 by switching resistors R3-y 1, R16-yi and Rl in parallel with resistor R16-yi. The amplifier is balanced by changing the base potential of the TZ-U1 transistor using resistor R9-yi, which is located under the slot. The beam is shifted vertically by resistor R2 by changing the base potentials of transistors T4-U1, T5-U1 in antiphase. The correction chain R2-yi, C2-U1, C1 carries out frequency correction of the gain depending on the position of switch B1.1.

To delay the signal relative to the start of sweep, delay line L31 was introduced, which is the load of the amplifier stage on transistors T7-U1, T8-U1. The output of the delay line is included in the basic circuits of the transistors of the final stage, assembled on transistors T9-U1, T10-U1, T1-U2, T2-U2. This inclusion of the delay line ensures its coordination with the stages of the preliminary and final amplifiers. Frequency correction of the gain is performed by the chain R35-yi, C9-U1, and in the final amplifier stage - by the chain C11-U1, R46-yi, C12-U1. Correction of the calibrated values ​​of the deviation coefficient during operation and change of CRT is carried out by resistor R39-yi, located under the slot. The final amplifier is assembled using transistors T1-U2, T2-U2 according to a common-base circuit with a resistive load R11-Y2... R14-Y2, which makes it possible to achieve the required bandwidth of the entire vertical deflection channel. From the collector loads, the signal is sent to the vertical deflection plates of the CRT.

Rice. 2. Structural scheme oscilloscope S1-94

The signal under study from the KVO pre-amplifier circuit through the emitter follower cascade on transistor T6-U1 and switch B1.2 is also supplied to the input of the KGO synchronization amplifier for synchronous triggering of the scanning circuit.

The synchronization channel (US block) is designed to run the scan generator synchronously with the input signal to obtain a still image on the CRT screen. The channel consists of an input emitter follower on the T8-UZ transistor, a differential amplification stage on the T9-UZ, T12-UZ transistors, and a synchronization trigger on the T15-UZ, T18-UZ transistors, which is an asymmetrical trigger with emitter coupling with an emitter follower on input to transistor T13-U2.

The base circuit of the T8-UZ transistor includes a D6-UZ diode, which protects the synchronization circuit from overloads. From the emitter follower, the clock signal is supplied to the differential amplification stage. In the differential stage, the polarity of the synchronizing signal is switched (B1-3) and amplified to a value sufficient to trigger the synchronization trigger. From the output of the differential amplifier, the clock signal is fed through the emitter follower to the input of the synchronization trigger. A signal normalized in amplitude and shape is removed from the collector of the T18-UZ transistor, which, through the decoupling emitter follower on the T20-UZ transistor and the differentiating chain S28-UZ, Ya56-U3, controls the operation of the triggering circuit.

To increase the stability of synchronization, the synchronization amplifier, together with the synchronization trigger, is powered by a separate 5 V voltage stabilizer on the T19-UZ transistor.

The differentiated signal is supplied to the trigger circuit, which, together with the sweep generator and blocking circuit, ensures the formation of a linearly varying sawtooth voltage in standby and self-oscillating modes.

The triggering circuit is an asymmetrical trigger with emitter coupling on transistors T22-UZ, T23-UZ, T25-UZ with an emitter follower at the input on transistor T23-UZ. The initial state of the startup circuit: transistor T22-UZ is open, transistor T25-UZ is open. The potential to which the C32-UZ capacitor is charged is determined by the collector potential of the T25-UZ transistor and is approximately 8 V. The D12-UZ diode is open. With the arrival of a negative pulse at the T22-UZ base, the triggering circuit is inverted, and the negative differential on the T25-UZ collector closes the D12-UZ diode. The trigger circuit is disconnected from the sweep generator. The formation of a forward sweep stroke begins. The scan generator is in standby mode (switch B1-4 is in the “STANDBY” position). When the amplitude of the sawtooth voltage reaches about 7 V, the triggering circuit through the blocking circuit, transistors T26-UZ, T27-UZ returns to the initial state. The recovery process begins, during which the timing capacitor S32-UZ is charged to its original potential. During recovery, the blocking circuit maintains the trigger circuit in its original state, preventing synchronization pulses from transferring it to another state, that is, it provides a delay in starting the sweep for the time required to restore the sweep generator in standby mode and automatically starts the sweep in the self-oscillating mode. In the self-oscillating mode, the scan generator operates in the “AVT” position of switch B1-4, and the startup and interruption of the trigger circuit occurs from the blocking circuit by changing its mode.

A discharge circuit of a timing capacitor through a current stabilizer was selected as a sweep generator. The amplitude of the linearly varying sawtooth voltage generated by the sweep generator is approximately 7 V. The timing capacitor S32-UZ is quickly charged through the transistor T28-UZ and the diode D12-UZ during recovery. During the working stroke, the D12-UZ diode is locked by the control voltage of the starting circuit, disconnecting the timing capacitor circuit from the starting circuit. The capacitor discharge occurs through the T29-UZ transistor, connected according to the current stabilizer circuit. The discharge rate of the timing capacitor (and, consequently, the value of the sweep factor) is determined by the current value of the T29-UZ transistor and changes when switching the timing resistances R12...R19, R22...R24 in the emitter circuit using switches B2-1 and B2- 2 (“TIME/DIV.”). The sweep speed range has 18 fixed values. A change in the sweep factor by 1000 times is ensured by switching the timing capacitors S32-UZ, S35-UZ with a switch Bl-5 (“mS/mS”).

The adjustment of the sweep coefficients with a given accuracy is carried out by the capacitor SZZ-UZ in the “mS” range, and in the “mS” range - by the tuning resistor R58-y3, by changing the mode of the emitter follower (transistor T24-UZ), which supplies the timing resistors. The blocking circuit is an emitter detector based on a T27-UZ transistor, connected according to a common emitter circuit, and on elements R68-y3, S34-UZ. The input of the blocking circuit receives a sawtooth voltage from the divider R71-y3, R72-y3 at the source of the TZO-UZ transistor. During the sweep stroke, the capacitance of the S34-UZ detector is charged synchronously with the sweep voltage. During the recovery of the scan generator, the T27-UZ transistor is turned off, and the time constant of the emitter circuit of the R68-y3, S34-UZ detector maintains the control circuit in its original state. The standby sweep mode is ensured by locking the emitter follower on the T26-UZ switch B1-4 (“STANDBY/AUTO”). In self-oscillating mode, the emitter follower is in linear operating mode. The time constant of the blocking circuit changes stepwise with switch B2-1 and roughly B1-5. From the scan generator, the sawtooth voltage is supplied to the scan amplifier through the source follower on the TZO-UZ transistor. Used in repeater field-effect transistor to improve the linearity of the ramp voltage and eliminate the influence of the input current of the scan amplifier. The sweep amplifier amplifies the sawtooth voltage to a value that provides a given sweep ratio. The amplifier is made of a two-stage, differential, cascode circuit using transistors TZZ-UZ, T34-UZ, TZ-U2, T4-U2 with a current generator on a transistor T35-UZ in the emitter circuit. Frequency correction of the gain is carried out by the capacitor S36-UZ. To increase the accuracy of time measurements, the device’s CVO provides for sweep stretching, which is ensured by changing the gain of the sweep amplifier by parallel connection resistors Ya75-U3, R80-UZ when closing contacts 1 and 2 (“Stretch”) of the ShZ connector.

Table 1. MODES OF ACTIVE ELEMENTS FOR DC CURRENT

The enhanced scanning voltage is removed from the collectors of transistors TZ-U2, T4-U2 and supplied to the horizontal deflection plates of the CRT.

The synchronization level is changed by changing the base potential of the T8-UZ transistor using resistor R8 (“LEVEL”), located on the front panel of the device.

The horizontal displacement of the beam is carried out by changing the base voltage of the T32-UZ transistor using resistor R20, which is also located on the front panel of the device.

The oscilloscope has the ability to supply an external synchronization signal through socket 3 (“Output X”) of the ШЗ connector to the T32-UZ emitter follower. In addition, there is a sawtooth voltage output of about 4 V from the emitter of the TZZ-UZ transistor to socket 1 (“Output N”) of the ShZ connector.

The high-voltage converter (unit U31) is designed to supply the CRT with all the necessary voltages. It is assembled on transistors T1-U31, T2-U31, transformer Tpl and is powered by stabilized sources +12V and -12V, which allows you to have stable supply voltages for the CRT when the supply voltage changes. The cathode supply voltage of the CRT -2000 V is removed from the secondary winding of the transformer through the doubling circuit D1-U31, D5-U31, S7-U31, S8-U31. The supply voltage of the CRT modulator is removed from another secondary winding of the transformer also through the multiplication circuit D2-U31, DZ-U31, D4-U31, SZ-U31, S4-U31, S5-U31. To reduce the influence of the converter on power supplies, the TZ-U31 emitter follower is used.

The CRT filament is powered from a separate winding of the transformer Tpl. The supply voltage of the first anode of the CRT is removed from the resistor YA10-U31 (“FOCUSING”). The brightness of the CRT beam is controlled by resistor R18-Y31 (“BRIGHTNESS”). Both resistors are located on the front panel of the oscilloscope. The supply voltage of the second anode of the CRT is removed from the resistor Y19-U2 (connected to the slot).

The backlight circuit in the oscilloscope is a symmetrical trigger, powered from a separate source of 30 V relative to the cathode power supply -2000 V, and is made using transistors T4-U31, T6-U31. The trigger is launched by a positive pulse removed from the emitter of the T23-UZ transistor of the trigger circuit. The initial state of the backlight trigger T4-U31 is open, T6-U31 is closed. A positive pulse drop from the trigger circuit moves the backlight trigger to another state, a negative one returns it to its original state. As a result, a positive pulse with an amplitude of 17 V is formed on the T6-U31 collector, with a duration equal to the duration of the forward scanning stroke. This positive pulse is applied to the CRT modulator to illuminate the forward sweep.

The oscilloscope has a simple amplitude and time calibrator, which is made on a T7-UZ transistor and is an amplifier circuit in limiting mode. The circuit input receives sine wave with the mains frequency. Rectangular pulses with the same frequency and amplitude of 11.4...11.8 V are removed from the collector of the T7-UZ transistor, which are supplied to the KVO input divider in position 3 of switch B1. In this case, the sensitivity of the oscilloscope is set to 2 V/div, and the calibration pulses should occupy five divisions of the vertical scale of the oscilloscope. The sweep factor is calibrated in position 2 of switch B2 and position “mS” of switch B1-5.
The voltages of the 100 V and 200 V sources are not stabilized and are removed from the secondary winding of the power transformer Tpl through the doubling circuit DS2-UZ, S26-UZ, S27-UZ. The voltages of the +12 V and -12 V sources are stabilized and are obtained from a stabilized 24 V source. The 24 V stabilizer is made using transistors T14-UZ, T16-UZ, T17-UZ. The voltage at the stabilizer input is removed from the secondary winding of the Tpl transformer through the DS1-UZ diode bridge. The stabilized voltage of 24 V is adjusted using the Y37-U3 resistor, located under the slot. To obtain sources of +12 V and -12 V, the circuit includes an emitter follower T10-UZ, the base of which is powered by resistor R24-y3, which adjusts the +12 V source.

When carrying out repairs and subsequent adjustment of the oscilloscope, first of all, it is necessary to check the DC modes of the active elements for compliance with their values ​​given in table. 1. If the parameter being checked does not fall within the permissible limits, you need to check the serviceability of the corresponding active element, and if it is serviceable, also the “piping” elements in this cascade. When replacing an active element with a similar one, it may be necessary to adjust the operating mode of the cascade (if there is a corresponding tuning element), but in most cases this does not have to be done, because the cascades are covered by negative feedback, and therefore the spread of parameters of the active elements does not affect normal operation device.

In the event of malfunctions associated with the operation of the cathode ray tube (poor focusing, insufficient beam brightness, etc.), it is necessary to check the compliance of the voltages at the CRT terminals with the values ​​given in table. 2. If the measured values ​​do not correspond to the tabulated ones, you need to check the serviceability of the components responsible for generating these voltages (high voltage source, KVO and KTO output channels, etc.). If the voltages supplied to the CRT are within the permissible limits, then the problem is in the tube itself and it needs to be replaced.

Table 2. DC CRT MODES

Notes:
1. Checking the modes given in table. 2 (except for contacts 1 and 14), is made relative to the device body.
2. Checking the modes on pins 1 and 14 of the CRT is carried out relative to the cathode potential (-2000 V).
3. Operating modes may differ from those indicated in the table. 1 and 2 by ±20%.

Oscilloscope model S1 73 is the most common domestic device for monitoring the shape of electrical signals and measuring their technical parameters in its class (electron beam). It has a lot of advantages: reasonable price, simple design, small dimensions and good performance properties. It is these advantages of the signal meter that have made it popular among technicians and radio amateurs.

Purpose and general information

The S1 73 brand oscilloscope is intended for conducting research procedures on electrical signals, which have the following characteristics:

• frequency range – from 0 to 5 MHz;
• amplitude – from 20 mV to 120 V (if an external 1:10 divider is included in the package, the range of the measured amplitude increases to 350 V);
• the ability to measure electrical voltage of both direct and alternating types;
• time interval range – from 0.4 µs to 0.5 s.

The C1 73 oscilloscope is powered both from a 220 V mains voltage (the delivery package includes a rectifier) ​​and from a 27 V constant voltage source. The device consumes about 19 W from a direct current source, and 30 W from an alternating current mains. The weight of the device is 3.2 kg and 4.5 kg with auxiliary rectifier. The display is an oscillographic cathode ray tube, has dimensions of 6x4 cm (WxH).

Important! Information about the rules of use can always be found in the operating instructions or freely available on the Internet.

Criterias of choice

Choosing an oscilloscope is not an easy task that requires a careful approach, since each device differs from each other in many parameters and properties.

When choosing the meter in question, you should pay attention to the following points:

1. Type of measuring electrical device - there are analog and digital. Analog oscilloscopes are distinguished from digital versions by the method of processing the incoming signal. Digital meters more advanced and powerful, but have a high cost and often complex management;
2. Installation method - they can be portable, or portable, stationary and with USB interface(convenient for car enthusiasts);
3. Bandwidth is the main characteristic of the meter. It is this that determines the range of measured electrical signals. Choosing by this parameter product, it is necessary to proceed from the characteristics of the signals of the measured object;
4. Sampling frequency (sampling frequency) – provides the declared bandwidth in real time for each channel;
5. Memory depth. The higher this indicator, the more complex the signals the electrical device can receive;
6. Number of channels – this parameter depends on how many channels a specialist needs to observe at a time;
7. Waveform update rate. The higher this indicator, the higher the probability of catching rare and random events, which is important for proper debugging of projects.

Technical characteristics of popular domestic oscilloscopes

On a note. The H3013 oscilloscope is a demonstration instrument and is usually used by teachers of educational institutions in laboratory classes. It is extremely difficult to find such a copy for sale in working condition.

Checking, setting and adjusting the device

Any measuring device, including an oscilloscope, needs to be checked regularly, since over time the device settings may become lost, or some radio elements may fail, which leads to incorrect measurement of parameters.

After any repair, or preferably on an annual basis, the electrical component of the meter should be checked and adjusted. These procedures can be performed in specialized centers or independently. However, to independently check the product parameters, you will need certain knowledge and the availability of the following equipment:

• voltmeter operating with high resistance;
• oscilloscope model S1 101 or S1-68 and the like;
• kilovoltmeter;
• ampere-voltmeter;
• frequency meter with an upper limit of at least 1 MHz;
• pulse signal generator.

Important! If the oscilloscope is used in research activities or a control and supervisory organization, then it must be verified on an annual basis by specialized bodies that issue a special dated permit for use.

An oscilloscope device is an indispensable device in electrical engineering that allows you to observe electrical waves. Also, not a single repair shop or scientific and technical laboratory can do without this meter. It is necessary to approach the choice of an oscilloscope carefully so that the measurement result is correct and satisfies the existing need.

Video

The Soviet Union produced a lot of good measuring equipment. One of the interesting specimens of that time was the portable oscilloscope S1-112. This is what we will talk about.

I got this oscilloscope for 2000 rubles. Three or four years ago. I then needed a simple, compact device at an equally modest price. Since then, it has served me faithfully when I need to dig into the guts of my next electronic homemade product.

The S1-112 was produced long before the collapse of the Brelin wall and the destruction of the USSR - since 1982. Like any device, this oscilloscope has several modifications: S1-112A, S1-112M, S1-112AM. The device is interesting because in addition to the oscilloscope, it has a built-in multimeter! In this case, the multimeter readings are displayed on the same CRT tube as the oscilloscope readings. A device was produced for testing and tuning industrial and consumer electronic equipment, for which frequency bandwidth was not critical.

In oscilloscope mode, the device can examine signals with an amplitude from 5 mV to 250 V, with a duration in the range from 0.12 μs to 0.5 s. They can examine a signal with a frequency of up to 10 MHz. In multimeter mode, it can measure constant pressure up to 1000 V and resistor resistance up to 20 MOhm. The device has small dimensions (250x190x110) and modest weight - only 3.6 kg. Among the shortcomings, I would name the small screen and plastic body.

As you can see in the photo, the internal structure of the C1-112 oscilloscope is quite compact. The designers took care of the economical use of the available housing space. In domestic reality, this plays an important role, since many radio amateurs do not have free space for numerous bulky, albeit good, devices.

The good accessibility to many tuning resistors is immediately striking. This plays a big role in calibrating and adjusting the device.

Working with S1-112

Using this device is a pleasure. Firstly, it is compact, and secondly, it is quite good, simple and ergonomic. It is quite convenient to switch between a multimeter and an oscilloscope. Of course, you won’t be able to view a signal with a frequency greater than 10 MHz properly. But it will be just right for assembling power supplies, amplifiers and other low-frequency equipment.

As you can see from this block diagram, the C1-112 is a fairly simple device (the multimeter is not shown on the block diagram). But that's what's good about him. Especially in the home amateur radio business. Therefore, if you need a cheap and good oscilloscope to set up your designs, then feel free to take the C1-112. It is significantly better than Chinese digital oscilloscope designs.