This circuit was found in a 90s Popular Electronics. It generates tones given by the oscillators and can be changed. The circuit already includes an amplification stage.
Using a ceramic resonator, it is possible to vary the frequency between 4.9 MHz and 5 MHz. The...
The circuit in the figure can be used to trigger a triac or even a comparator in a project that...
This is a circuit with two switches, one turns on and the other turns off for DC loads using SCR....