Oscilloscope measurement voltage range_Oscilloscope measurement voltage maximum range

Oscilloscopes are widely used test instruments. They can be used to observe the waveform curves of various signal amplitudes changing over time. They can also be used to test various electrical quantities, such as voltage, current, frequency, phase difference, amplitude modulation, etc. What is the maximum voltage range of an oscilloscope? This article will give you the answer.

Oscilloscope voltage measurement maximum range

It is written on the panel of the oscilloscope. For example, the common TEK oscilloscope has 1M ohm 300V.50 ohm 5V (50 ohm is only available on better oscilloscopes).

That is to say, the maximum input voltage of the oscilloscope port is 300V at 1M ohm input and 5V at 50 ohm input. If your oscilloscope does not have this option, it is usually 300V. The maximum input voltage allowed by the oscilloscope port is 300V. The general probe is 1X or 10X. If you use 1X, then you can only add 300V (peak) to the probe at most. If you use 10X, theoretically you can add 3000V to the probe. However, since the insulation performance of the probe may not be sufficient, you should determine the voltage that can be added according to the manual of the probe.

Finally, I would like to emphasize that the ground clip of the oscilloscope can only be clamped at a position where there is no voltage difference with the ground. Otherwise, it will catch fire and burn things.

Notes on using an oscilloscope

For the safety of the instrument operator and the instrument, the instrument should work normally within the safe range to ensure the measurement waveform is accurate and the data is reliable. Please note:

1. If the user needs to measure the floating signal test of switching power supply (switching power supply primary, control circuit), UPS (uninterruptible power supply), electronic rectifier, energy-saving lamp, inverter and other types of products or other electronic equipment that cannot be isolated from AC220V mains, the DP100 high-voltage isolation differential probe must be used.

2. For general oscilloscopes, adjust the brightness and focus knobs to minimize the diameter of the light spot to make the waveform clear and reduce test errors; do not let the light spot stay at one point, otherwise the electron beam will bombard one point and form a dark spot on the fluorescent screen, damaging the fluorescent screen.

3. The housing of a general oscilloscope, the metal outer ring of the signal input BNC socket, the probe ground wire, and the AC220V power socket ground wire are all connected. If the instrument is not connected to the ground wire when in use, and the probe is used directly to measure the floating signal, the instrument will have a potential difference relative to the ground; the voltage value is equal to the potential difference between the point where the probe ground wire contacts the device under test and the ground. This will bring serious safety hazards to the instrument operator, the oscilloscope, and the electronic equipment under test.

4. Measurement system - such as oscilloscopes, signal sources; printers, computers and other equipment. Electronic equipment under test - such as instruments, electronic components, circuit boards, power supplies for equipment under test, etc. The grounding wire of the equipment must be connected to the public ground (earth).

5. When the TDS200/TDS1000/TDS2000 series digital oscilloscope is used with a probe, it can only measure the waveform of the signal (the measured signal - signal ground is the earth, and the signal end output amplitude is less than 300V.CAT.II). It is absolutely not allowed to measure the floating ground signal of AC220V or electronic equipment that cannot be isolated from AC220V. (The floating ground cannot be connected to the earth, otherwise it will cause damage to the instrument, such as testing an induction cooker.)

Other precautions when using an oscilloscope

(1) Thermal electronic instruments should generally avoid frequent startup and shutdown, and the same applies to oscilloscopes.

(2) If you find that the waveform is affected by external interference, the oscilloscope casing can be grounded.

(3) Before shutting down the power, turn the brightness adjustment knob counterclockwise to the bottom to reduce the brightness to the minimum, and then turn off the power switch.

(4) When observing the bright spot on the screen and making adjustments, the brightness of the bright spot should be moderate and not too bright.

(5) The voltage of "Y input" should not be too high to avoid damaging the instrument. It should not exceed 400V at maximum attenuation. When the "Y input" wire is suspended, it will be interfered with by external electromagnetic interference and produce interference waveform. This phenomenon should be avoided.