Found in a documentation from the 90's, this circuit uses only one integrated circuit. The resistors in series with the LEDs depend on the power that can be between 5 and 12 V.
This circuit monitors the current in the negative line. The circuit is from a 2005 Linear...
This circuit is from an August 1984 Radio Electronics magazine. It monitors the state of a RAM...
The frequency of this oscillator depends on the crystal used and has a threshold given by the...