Low temperature sensor (CB7814E)

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

20 W amplifier TDA1520Q (CB16670E)
This powerful amplifier was part of commercial sound circuits from the 90s. The integrated circuit...
500 Hz Tone Emitter (CB13469E)
This circuit generates a control tone that serves to adjust amplifiers, check audio cables. The...
Locked Micro Alarm (CB1513E)
This circuit locks when the sensors are opened. The relay can be 6 or 12 V depending on the power...