This circuit, for vehicles with a 6 V battery, was found in the 1964 RCA transistors manual. Transistor 2N3054 can be replaced by a TIP41.
We found this circuit in an old American documentation. SCRs can be modern equivalent types. The...
We found this circuit in a 1990 documentation. The operational amplifiers are type 741 and the LED is...
This fast-acting circuit uses a 555. We found it in the November 1992 Radio Electronics magazine. The...