Solar radio (CB20485E)

This circuit is from a 1991 publication. The integrated circuit used is an integrated radio from that era.

4046 Alarm Clock (CB25768E)
This circuit uses a PLL4046 oscillator to excite a piezoelectric ceramic. The circuit is from an...
Simple metal detector (CB7960E)
This circuit already explored in several diagrams in this section was found in a 90’s Popular...
CMOS Logic Probe (CB12014E)
This logic probe or logic level indicator is suitable for use in CMOS circuits. The power comes...