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 circuit is very critical in the adjustment. The coil should have at least 1000 turns of fine...
By pressing and releasing PB1, only one LED is lit, drawing a number from 1 to 6, as in a die. The...
This electromyography monitor is from a 1978 publication on operational amplifiers. The components are...