This switched power supply was found in a 70s documentation. The basic components are from that time. The circuit operates at 200 kHz and has a ripple below 200 mV.
This tone-modulated transmitter produces a tone with frequency depending on C4 and C5. Free...
This circuit, from a 1999 publication, uses an improvised optical coupler with LED or...
This microphone preamplifier can be used in a variety of applications. The circuit is from a Radio...