This detector with ultra-low deviation was found in an American documentation from the 90s. Operational amplifiers are from that time. The power supply must be symmetrical.
Found in an English Maplin magazine in 1983, this circuit has an RIAA equalization. We suggest its...
We found this circuit in a 1991s PE Hobbyst Handbook. The circuit fires 10 LEDs that can control...
This alarm with NO and NC sensors was found in the January 1975 Radio Electronics magazine. The...