We found this circuit in a 1996 publication. The circuit uses components that are still common. The timing depends on C1, which can be changed, and the triac can be of any type.
Found in an old English documentation, this circuit is intended to amplify signals in the 2-meter ham...
The operational amplifier used in this circuit is a low voltage type from Texas Instruments, being...
We found this circuit in documentation from the 1980s. It drives an old cassette or roller type...