This circuit is from 1999 documentation. The integrated circuit used is not very common today. Both transistors are used if the motor current is greater than 500 mA.
This amplifier, found in a 1980s documentation, should be powered by a symmetrical source. Modern...
This is a voltmeter with high input resistance. The transistor is germanium. We found it in an...
Up to some minutes intervals can be obtained from this circuit. The circuit can use a lamp (or...