Continuity test (CB9328E)

This audible continuity test was obtained in a book from the 90's describing simple projects. The feeding is done with a single battery.

| Clique na imagem para ampliar |

LM3914 with Overscale Alarm (CB25112E)
The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale...
TTL Siren (CB18966E)
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
Crystal Controlled Signal Source (CB6147E)
This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals...