With the configuration shown in the figure, we have the relay being activated when the microphone picks up a sound and shutdown when the X1 reset sensor is activated.
In the figure we have the way to connect 6 solar cells in order to obtain higher voltage and...
This circuit has a maximum frequency of 10 kHz and a linearity better than 0.01%. The circuit is...
This circuit was obtained in a 1961 magazine, but it can be easily assembled today, as the...