This is audible light sensor circuit that is based the IC741 op-amp IC. This circuit light sensor one,these are use two LDRs for detector lower lightly.
The 741 is pulse oscillator generator output to small speaker. The VR1 have value 50k acts as to fine sensitivity of light sensor. The speaker use small size only because output has low current.
S:eleccircuit.com
EmoticonEmoticon