This simple circuit can work with either 4.5 V or 6 or 9 V if a 1k resistor is added in series with the set of LEDs. The circuit is from an old French publication.
September 2016 - It can be obtained from Mouser Electronics a kit for developing wireless remote...
This circuit is from an old documentation using OP27. This operational amplifier is not common...
For the 1 MHz frequency, the pass band of this filter is only 120 Hz wide. The filter is suitable for...