This 10 kHz filter was obtained from an article in Electronics Now magazine in February 1995. The power supply is dual and other equivalent operating conditions can be used.
This circuit uses an LDR as a sensor to trigger an LED indicator at a preset lighting level. The...
We found this circuit in an American publication from the 80's translated into Portuguese. The...
We found this circuit in an old French documentation from the 70s, but it can be assembled using...