This circuit was found in the March 1992 issue of Radio Electronics magazine. The circuit has several adjustments and uses an operational amplifier. Note the supply voltage.
This is the basic configuration of an operational amplifier sample & hold circuit. The FET and...
This circuit can be found in other projects in this site. When S1 is open the circuit produces...
This well-crafted speed game setup for two competitors was found in a 1998 Poptronics. The circuit...