Low temperature sensor (CB7814E)

Found in 90s Radio Electronics, this circuit is indicated for reading temperatures below zero.

Three Tone Oscillator (CB12661E)
From an old manual of unijunction transistors, this oscillator generates different tones when the...
Voltage Regulator 100 V x 20 mA (CB12670E)
A negative floating regulator capable of supplying an output voltage of -100 V with regulation of 20 mV for...
Toxic Gas Detector (CB6365E)
Found in a Hands On Electronics of the 80s, this circuit makes use of a gas sensor of the time....