Measuring voltage might be the most commonly performed measurement in electronics. This Project is a simple DC voltmeter that will let you measure up to 10 volts. You can see from the schematic what a simple Project this is.
The Meter itself can handle 0.16 volts. To measure larger voltages, resistors must be inserted in series with the Meter to reduce the voltage down to 0.16 volts.
To use this circuit, you'll have to connect the long wires so that the + side of the voltage is connected to the + long wire and the - side of the voltage to the - long wire. Turn power ON and you'll notice the Meter move according to how large the voltage is.
First try measuring the voltage of the Batteries. (This circuit is a handy way to check batteries used in flashlights, toys, etc.) You might also want to use this Project to measure voltages at different points in other Projects. You might want to measure the voltage drops across diodes and resistors ... or measure voltages from emitter to base and from collector to emitter in transistor circuits.
Don't try to measure voltage if you think the voltage might exceed ten volts. And don't try to measure a voltage in any device that's plugged into an AC wall outlet. If you apply more than 10 volts to this circuit, or try to measure an AC voltage, the Meter will be damaged.