This 80's Exar circuit has a carrier detector for frequencies up to 500 kHz. The circuit uses a company 567 which is still a common component.
In this phase shift circuit, the transistor can be any general-purpose transistor. The circuit is from...
This low-power intercom can be powered by solar cells. The circuit is two-way, with an integrated of the...
The resistors R1 and R2 consist of 8 220 ohms x 2 W resistors connected in parallel. The...