Found in a 90s Popular Electronics, this circuit uses a 741 to generate frequencies from 0.1 to 30 Hz. Observe the phototransistor feedback.
This 80's Motorola circuit can generate 100 MHz signals, but they can reach 200 MHz with the...
Of course, the current is extremely small, but a voltage of 300 V can be obtained from 9 V of a...
We found this solid-state relay circuit that can function as a shield in a Radio Electronics...