Non Inverting Amplifier (CB6437E)

This non-inverting AC amplifier was found on a Popular Electronics. The setting applies to any operational amplifier.

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...