This circuit, obtained from a 1965 magazine, can still be assembled using some modern equivalent components. The transistors may be BC558 and the transformer is obtained from a disused transistor radio.
This light comparator is of the window type already explored on this website in several...
Using the integrated circuit DCP01051D this circuit was found in the magazine Electronics Now of...
This filter with the operational 741 passes the frequency range between 300 Hz and 3,400 Hz. This...