We found this circuit in a 1987 documentation. It is a multi-tester with neon lamp and LEDs operating with both low continuous voltage and high alternating voltage.
This is another possible version of a negative voltage generator using a 555 integrated circuit. The...
This timer activates a relay after a time interval of up to 15 minutes has elapsed, starting from...
This circuit was used to regulate the speed of small DC motors of cassette recorders. However, if the...