This circuit with two 555s was found in the Encyclopedia of Electronic Circuits volume 5 of 1995. The power is high due to the use of 2N3055.
With the configuration shown in the figure, we have the relay being activated when the microphone picks...
We found this circuit in a 1992 Poptronics. What it does is to activate LEDs sequentially,...
In the figure we have an application of a voltage comparator in a circuit that fires with the...