This circuit has the intensity of the signals controlled by the light that falls on the sensor. Note that it is not a frequency-controlled oscillator. Equivalent transistors can be used.
Unlike the previous circuit, this circuit from Electronics Now, October 1993, has the load...
For the component values used in thisf this circuit, the frequency can be adjusted between 740 Hz and...
We found this circuit in the 1982 Selezione Radio magazine in Italy. The circuit uses an...