This automotive grade circuit was found in a 1991 Electronics Hobbyist. The transistors are general purpose types. P1 sets the monitoring voltage.
The figure shows how to use the LM3914 bargraph with expanded scale. The circuit has two...
This receiver activates a relay from signals emitted by a 27 MHz modulated transmitter as...
The transistor in this circuit can be replaced with any general-purpose equivalent. The time...