Found in the June 1987 issue of Radio Electronics magazine, this circuit uses well-known CMOS components. The circuit has a CMOS amplifier stage that drives a small speaker.
This circuit uses two light-activated SCRs or LASCRs, uncommon components today. The power depends on...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...