Toy electronic chicken

Circuit Overview :

The following figure is a circuit that simulates the sound of a chicken. When a handicraft pompom chicken is equipped with this circuit, it will become lifelike and more attractive. If it is placed in a small box, you can get the effect of hearing the sound but not finding the shadow, which is full of interest.

       Working principle:

The transistors BG1pBG2 form a direct-coupled amplifier. The collector voltage of the BG2 tube is fed back to the base of the BG1 tube through C2, so that the circuit generates audio oscillation. The input circuit of the BG1 tube is connected to the series resonant circuit composed of LpC1, which will cause the circuit to generate low-frequency intermittent oscillation to modulate the above audio signal, so that the speaker can emit a clear and realistic sound of "jiya pjiya".

       Component selection and production:

BG1 uses 9014, BG2 uses 9015, and L uses a 12mH color-coded inductor. In order to reduce the size, the circuit board should be designed to be as small as possible. The speaker Y uses an ultra-thin 8Ω, 0.25W internal magnetic small speaker so that it can be easily placed in the toy chicken. The circuit uses fewer electrodes, and a No. 5 battery can be used for several months. As long as the circuit is soldered correctly, it can generally work normally without debugging.