This optical theremin was found in a 90s Hands-On Electronics. The basic frequency is given by C1 and the output is made in a speaker through a small output transformer.
The circuit shown in Figure bellow generates frequencies of 50 Hz, 100 Hz, and 200 Hz. The circuit uses a...
This circuit rejects frequencies around 1 kHz and can be adjusted using C1. Equivalent operational...
From stereo inputs, this circuit generates a modulated and multiplexed signal to be transmitted in the FM...