This simple three-LED sensor uses an NTC at the input. The circuit is based on an uncommon integrated component today. We found it in documentation from the 80s.
The circuit shown in figure 6 provides a TTL logic signal at its output, when the LM3911...
This circuit is from 1950, from the time when some still called the crystal triode transistor. The circuit is...
This ultrasonic insect repellent was found in American documentation from the 1980s. The...