If you have the skills and can get your hands on SMD components, you can assemble this small amplifier. We found it in the Radio Electronics Experimenter special edition from 1990.
Available at Mouser Electronics this component of Diodes Incorporated consists of a voltage...
Found in Radio Electronics this circuit uses a fotodiac to drive a triac. The circuit can use...
The first circuit was suggested by Analog Devices (www.analog.com) in its Application Note AN-411...