This CMOS 4001 oscillator alternately turns the relay on and off at times set by R2. The circuit is from Electronics Now magazine, June 1995.
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,...