Solar timer (CB20498E)

This very low consumption circuit can be powered by a solar cell. The time indication is given by a microammeter.

High Impedance Microphone Preamplifier (CB18257E)
This high-gain circuit uses junction FETs (JFETs) and must be powered by somewhat high voltages. The...
Binary Display 7400 (CB22436E)
This circuit counts 1 per second, displaying the value in binary. The circuit is TTL and must be...
Sensitive Geiger Detector (CB5925E)
Critical components of this project are the Geiger tube and the 300V battery. The battery can be...