This circuit with the PLL4046 was found in the October 1994 Electronics Now magazine. The transistor is low power, and the volume obtained is small.
This network can be used in a sound project to control the tone. The circuit is from an...
Published by Philips in 1965 documentation, the sensor for this circuit is a common LDR. The...
This circuit operates at a voltage of 1.3 V from a single mercury cell. We found in an old...