This receiver uses old transistors that are equivalent to BC548 and BC558. The photo diode is of any type. The receiver can be used on a highly sensitive audio link.
This circuit for triggering a CMOS gate without rebounding was found in the October 1974 issue of...
This generator is more complete than the previous one, being able to generate pulses as indicated...
This 1975 circuit for automotive applications replaces the mechanical vibrator found in old cars...