The purpose of this circuit is to indicate which of the two cars crosses the finish line first on a slot car lane. The circuit is from an 80's Popular Electronics.
This is yet another version of the light-controlled oscillator that can be found on this website. This...
Originally created to feed the filaments of a 12AX7 as an audio preamplifier to eliminate the...
The incidence of light in the LDR causes this circuit to start operating, emitting a sound whose...