What Is an Oscillograph?

An oscilloscope is a very versatile electronic measuring instrument. It can transform electrical signals that are invisible to the naked eye into visible images, which is convenient for people to study the changes in various electrical phenomena. An oscilloscope uses a narrow, high-speed electron beam that hits a screen coated with a fluorescent substance to produce tiny light spots (this is how traditional analog oscilloscopes work). Under the action of the measured signal, the electron beam is like the pen tip of a pen, which can trace the change curve of the instantaneous value of the measured signal on the screen. With an oscilloscope, you can observe the waveform curves of various signal amplitudes over time. You can also use it to test various electrical quantities, such as voltage, current, frequency, phase difference, amplitude adjustment, and so on.

An oscilloscope is an instrument used to measure the shape of an alternating current or pulsed current wave. It is composed of a tube amplifier, a scanning oscillator, and a cathode ray tube. In addition to observing the waveform of the current, you can also measure the frequency and voltage intensity. Any periodic physical process that can become an electrical effect can be observed with an oscilloscope.

Classification by signal

The analog oscilloscope uses an analog circuit (oscilloscope, the basis of which is an electron gun). The electron gun emits electrons to the screen. The emitted electrons are focused to form an electron beam and hit the electron beam.

Oscilloscopes can be divided into analog oscilloscopes and digital oscilloscopes. For most electronic applications, both analog oscilloscopes and digital oscilloscopes are competent. However, for some specific applications, due to the different characteristics of analog oscilloscopes and digital oscilloscopes, Appropriate and unsuitable places appear.

No light spots or waveforms

Power is not turned on.

The brightness knob is not adjusted properly.

X, Y axis shift knob position adjustment.

The improper adjustment of the Y-axis balance potentiometer caused serious imbalance in the DC amplifier circuit.

Unable to spread horizontally

The trigger source selection switch is set to the external position and there is no external trigger signal input.

Precautions

The safety of the instrument operator and the safety of the instrument. The instrument works normally within the safe range to ensure accurate measurement waveforms and reliable data. Attention should be paid to:

1. The general oscilloscope minimizes the spot diameter by adjusting the brightness and focus knobs to make the waveform clear and reduce test errors; do not leave the spot at a fixed point, otherwise the electron beam hits a spot and it should form a dark spot on the phosphor screen and damage the phosphor screen.

2. Measurement systems-such as oscilloscopes, signal sources; printers, computers, etc. The electronic equipment under test-such as instruments, electronic components, circuit boards, power supply of the equipment under test, etc. The ground wire of the equipment must be connected to the public ground.

3 When TDS200 / TDS1000 / TDS2000 series digital oscilloscopes are used with probes, they can only measure the waveform of the signal (the signal to be measured-the signal ground is the ground, and the signal terminal output amplitude is less than 300V CAT II). Never measure the floating signal of the mains AC220V or electronic equipment that cannot be isolated from the mains AC220V. (The floating ground cannot be connected to the ground, otherwise the instrument will be damaged, such as testing the induction cooker.)

4 The shell of the universal oscilloscope, the BNC socket metal outer ring of the signal input end, the probe ground wire, and the AC220V power socket ground wire end are all connected. If the instrument is not connected to the ground wire and the floating signal is directly measured with the probe, the instrument will generate a potential difference; the voltage value is equal to the potential difference between the probe ground wire contacting the point of the device under test and the ground. This will pose a serious safety hazard to the instrument operator, the oscilloscope, and the electronic equipment under test.

5. If the user needs to measure switching power supply (primary switching power supply, control circuit), UPS (uninterruptible power supply), electronic rectifiers, energy-saving lamps, inverters and other types of products or other electronic equipment that cannot be isolated from the mains AC220V for floating signal testing , Must use DP100 high-voltage isolated differential probe.

Digital oscilloscope

Other precautions in using the oscilloscope:

(1) Thermal electronic instruments generally avoid frequent startup and shutdown, as is the case with oscilloscopes.

(2) If the waveform is found to be affected by external interference, you can ground the oscilloscope case.

(3) The voltage of "Y input" should not be too high, so as not to damage the instrument, and it should not exceed 400 V at the maximum attenuation. When the "Y input" wire is suspended, interference waveforms will appear due to external electromagnetic interference. This phenomenon should be avoided.

(4) Before turning off, turn the brightness adjustment knob to the bottom counterclockwise to minimize the brightness, and then turn off the power switch.

(5) When observing and adjusting the bright spots on the screen, the brightness of the bright spots should be moderate and not too bright.

Oscilloscopes are divided into multi-purpose oscilloscopes, digital oscilloscopes, analog oscilloscopes, virtual oscilloscopes, arbitrary waveform oscilloscopes, handheld oscilloscopes, digital fluorescence oscilloscopes, and data acquisition oscilloscopes ^[1] .