This circuit was found in a 1969 Mullard documentation. Used transistors can be replaced with modern equivalents. Output transistors may be BD135 and 136 with heatsinks.
This circuit can also use other series operational amplifiers such as MC33172, MC33174, MC35171,...
The AC125 transistor is an ancient germanium type widely used in audio stages as a preamplifier. In the...
The pass-through alarm we present uses an infrared (IR) emitter as a sensor. When cutting the...