Toy electronic cat circuit (1)

The working principle of the circuit : When you clap your hands, the sound is converted by the piezoelectric ceramic chip HTD detector
into an electrical signal and sent to the transistor VT1 for amplification. After being amplified, it is coupled to the 2nd pin of the time base
circuit , so that the 3rd pin of the 555 outputs high voltage. flat. At this time
, the meowing oscillator composed of VT2, VT3, T, B, etc. receives power and starts to operate, and speaker B emits a meowing
sound.