This circuit interrupts the power supply when grounding is missing. The circuit is from an old documentation (from the 80's) using current transformers and other components of the time.
The crystal used in this oscillator can have frequencies up to 30 MHz or more, depending on the...
This circuit increases the sensitivity of a multimeter in the measure of small alternating...
This circuit is from a documentation from the 50's. The transistors are made of germanium. The...