This circuit uses a transistor as a sensor and operates in the range of 0 to 50º C. We found it in old documentation. Operational equivalents can be used.
We found this circuit in a 1976 documentation, but it can still be easily assembled using BC548...
This circuit of an old publication produces the insect-like noise that drives them away. The...
This circuit aims to increase the selectivity of receivers whose FI is 455 kHz. The circuit is...