Employing the XR2206 IC, this circuit was found in the May 1977 issue of Radio Electronics magazine. The formula next to the diagram gives the component values as a function of frequency.
This SCR relaxation oscillator was found in an 80's Electronic Design. It flashes a small...
We found this shield circuit in a 1991 technical documentation. The phototransistor can be...
This circuit for old photo enlargers was found in a 1970s RCA manual. The components are from the...