Based on the LTC3862, this circuit consists of a DC-DC converter capable of operating with input voltages lower than the desired output. MOSFET admits equivalent.
The circuit in the figure is based on an LM101A; diodes can be replaced with equivalents. The...
This circuit, with magnetic sensor, uses an operational amplifier of the time. The circuit is from...
Found in a 90s Popular Electronics, this circuit checks if a remote-control transmitter is...