TTL signal injector (CB22431E)

This simple circuit must be powered by a voltage of 5 V. The integrated circuit is the 7400, but other gates configured as inverters can be used.

Continuity tester (CB9326E)
This circuit was obtained in an Electronics Now from the 90s. The circuit uses operational...
Physiotherapy Ultrasound (CB16841E)
This circuit operates at a frequency around 1 MHz, having been found in a technical documentation from...
Integrated Transmitter without Coil (CB14821E)
The TAA131 used in this circuit is not very easy to find today, but an equivalent low power audio...