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.
This low voltage AC control uses a triac. Any TIC series triac can be used and this device must be...
This circuit was found in a 1987 magazine. It measures the pulse rate produced by a cardiac...
The field effect transistors have characteristics that allow the realization of excellent...