This circuit is from a Radio Electronics from February 1959. The circuit has a speaker output and good sensitivity. Power is supplied from a 9 V battery.
This circuit was obtained in Linear Technology documentation from 1993. The circuit provides 3.3 V and...
Found in the August 1994 issue of Electronics Now, this CMOS circuit uses the 4046, which is...
We found this circuit in the December 1994 Electronics Now magazine. The worthless components are...