Alarm siren (CB26231E)

This circuit with two 555s was found in the Encyclopedia of Electronic Circuits volume 5 of 1995. The power is high due to the use of 2N3055.

| Clique na imagem para ampliar |

Carbon Microphone Preamplifier (CB14801E)
Carbon microphones are no longer used in most projects. However, finding one in the scrap metal, it...
Sonic Repellent for Animals (CB13162E)
This circuit produces a strong tone of audio or ultrasound, depending on the values of components C1 and...
Alarm (CB12604E)
This alarm from an old 1978 publication uses PNP transistors and driver and output transformers that are...