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.
This solid-state relay (SSR) or shield was found in a 1995 Electronics Now. The transistor can be...
The components used in this National Semiconductor circuit are not common today, but the...
The circuit presented in the figure is an amplifier for stereo sources with the Maxim MAX9723...