This circuit is from a 1968s Motorola documentation. The load can range from 10 to 100ohm and the transistor supports a modern equivalent such as 2N2222 or BD135.
Disabling this circuit from a 2002 documentation can only be done by pressing 4 keys in a correct...
This circuit was found in a 1979 magazine. We can use any JFET like MPF102 or BF245. The relay is 12 V...
This circuit was obtained in a 90’s documentation. The operational amplifiers are from that time....