This power step for relay activation was found in the 1964 RCA transistors manual. The circuit is of the NF type and the transistors admit equivalents. R4 depends on the drive voltage.
The CMOS 4046 integrated circuit is not very common today, consisting of a very efficient PLL for...
This old circuit is suitable for signaling applications. The lamp must be incandescent, and the...
In the figure we show how the half wave rectification of a signal can be done using an operational...