This 4 1/2 digit digital voltmeter circuit was published in the April 1993 Electronics Now magazine. The circuit uses the integrated component of the time and has 5 voltage ranges.
In the circuit shown in the figure we have the way to excite a small speaker from a TTL output. The...
This simple circuit is from a Radio Electronics from August 1952. The current depends on the...
Found in an Electronic Design, this small power source uses a battery as a voltage reference,...