This Power supply sources from 500 to 1,000 mA according the transformar and was found in a publication of the year 1958. The diodes can be now the 1N4004 and the transistor should be mounted on a heatsink.
We found this circuit in a 1995 documentation. It can measure frequencies from 100 kHz to over 100 MHz...
The simple optical intercom we show is from a 1995 documentation. The LEDs can be infrared or...
Suggested by General Electric, this circuit with triac is able to reverse the rotation of a motor...