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.
Found in a 2005 Linear Technology application manual, this circuit provides outputs from a current...
This circuit appears in other articles and suggestions for circuits in this section from other...
The phototransistor of this alarm can be of any type. The relay must be sensitive type according...