Relays up to 100 mA can be driven by the 555 with the recommended circuit. The circuit is from an article in the September 1992 Radio Electronics magazine.
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,...