Recently, much has changed for the better in the market for measuring instruments. Compact digital multimeters designed to measure current, voltage, resistance, which operate in a fairly wide range, have appeared on sale. Many of them are equipped with additional functions, for example, they can operate in the “ringing” mode of the circuit or measure the transistor coefficients. They always include a digital voltmeter. Voltage measurement is the main stage in the development, repair or commissioning of electronic devices of any complexity.
Having a digital voltmeter in your home laboratory is necessary for many reasons. Such devices are compact and quite reliable in operation. Moreover, amateur radio operation is impossible without measurements, and a lot depends on the quality of measurements. The main difference between these devices and analogue “compatriots” is the high
internal resistance, which is the guarantor of correct readings when working in low-current circuits. A digital DC voltmeter is able to measure the voltage at the output of the microcircuit and not “draw” the electric circuit. This is especially true when working in process control circuits. Any intervention in this case can lower the level of the control signal by voltage and cause a malfunction in the operation of the entire production line. Digital devices are free from this drawback and are absolutely safe to use.
But not everything is “cloudless", and you should not completely trust the latest in
measuring instruments . A digital voltmeter behaves very poorly on lines and in AC circuits. In other words, when trying to measure in a long electric circuit, provided there is a small load at the output of this circuit, we are likely to get incorrect results. This may be due to the high level of “pickups” that are superimposed on the main signal. Also, a digital AC voltmeter is designed to work in standard frequency circuits and when it changes, it starts to work with errors. The same can be said about work in circuits with an
electric voltage that differs in shape from a sinusoid (triangular, rectangular, etc.).
Ordinary pointer device in this regard is much better than its digital competitor. He has a low input impedance, and when working with the line he “draws” all the pickups and shows the real voltage in the network. As for measuring voltage of a non-standard frequency, the device does not know what fifty Hertz is. It will show the average measured value.
Based on the foregoing, we can draw some conclusions. A digital voltmeter is conveniently used in a home laboratory, for example, when repairing electronic circuits. In the best way, this device shows itself in DC circuits of small length.
The best option is to equip your laboratory with several types of measuring instruments, so to speak, "for all occasions." In this case, you will be well prepared and will surely be able to solve any, even quite complex, task.