This 100 second timer was found in the September 1992 issue of Radio Electronics magazine. The circuit has two timing ranges and time adjustment at R6.
This 80's circuit uses an audio amplifier to obtain a symmetrical source from a single source. The...
I found this circuit in a 1986 English magazine. It can still be easily assembled, exchanging Q1...
Found in a 1970s documentation, this circuit has a flat response from 15 Hz to 130 kHz. Modern...