This circuit was found in a 73 magazine for radio amateurs from the 90s. The circuit uses high voltage transistors and the relay is high voltage as well.
This oscillator employs a Motorola operational amplifier common in the 70s. We can implement the...
This two transistor audio amplifier stage was found in a publication of the year 1968. The...
This sound effects circuit is based on 555 rectangular oscillating circuits but produces...