This circuit is suitable for calibrating old oscilloscopes. It was found in a 1980s documentation. It generates precise signals given by the crystal.
This circuit generates signals in the range of 5 to 15 MHz. We found it in an English...
This circuit can use NTCs from 200 to 680 ohms, just change P2. For 200 ohms use 330 ohms, for 250...
This basic circuit is from an old documentation. The relay must be 50 mA maximum and must have a...