Humidity Monitor (CB24940E)

Using a period sensor, this circuit was found in the February 1986 issue of Radio Electronics magazine. The sensor is a Philips of the period.

| Clique na imagem para ampliar |

Stepper motor as encoder (CB21248E)
In the figure we have the way to use a stepper motor as an encoder. Operational amplifiers can be of...
Refrigerator Alar (CB1351E )
Placed inside the refrigerator, this circuit triggers an oscillator when the part is opened...
Smoke Alarm (CB13235E)
We found this circuit in an old documentation from the 70s, but it can be assembled with more...