Unijunction metronome (CB21701E)

This traditional metronome circuit is powered by voltages from 9 to 12 V and output drives a common speaker.

General Purpose Preamplifier (CB4772E)
Circuits similar to this appear elsewhere in this section. The transistors can be BC549 (low...
Acid rain monitor (CB7992E)
This circuit indicates when a rain is acidic by monitoring its pH. The circuit is from a 90s RE...
Triggered Clock (CB16014E)
In a microprocessor project (shield) for control applications, a triggered clock can be useful....