Touch switch (CB8727E)

Found in a 90s Popular Electronics, this touch switch uses a single sensor. PLLs are common today. Observe the supply voltage range.

| Clique na imagem para ampliar |

Electroscope (CB4341E)
This simple electroscope with bipolar transistors is not the most sensitive, but can detect static...
Multi Frequency Oscillator (CB4226E)
This oscillator for various frequencies was obtained from a 1980s telecom documentation. The...
Water-Activated Triac Switch (CB24054E)
This circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V...