This simple indicator circuit was found in a documentation from the 90s. Trimpots can have values between 2k and 10k, a series resistor is recommended to limit the current to the minimum setting.
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...