Music hypnosis circuit based on CIC2851

9014 is a very common crystal triode. It is often seen in radios and various amplifier circuits. It has a wide range of applications. It is an npn-type low-power triode, 9014 triode parameters: collector maximum dissipated power PCM=0.4W (Tamb =25°C); collector maximum allowable current ICM=0.1A; collector base breakdown voltage BVCBO=50V; collector emitter breakdown voltage BVCEO=45V; emitter base breakdown voltage BVEBO=5V; collector The emitter saturation voltage drop VCE(sat)=0.3V (IC=100mA; IB=5mA); the base emitter saturation voltage drop VBE(sat)=1V (IC=100mA; IB=5mA); the characteristic frequency fT=150MHz .
The music hypnosis consists of two parts: a timing circuit and a music sounding circuit. The specific circuit is shown in the figure. Transistor VTl ~ VT3 constitute a timing circuit; ICl music integrated circuit CIC2851 and triode VT4 and other components constitute a music sound circuit. When the button switch SB is pressed, Cl is charged, and VT1 and VT2 are turned on. After the SB is released, VT1 and VT2 can remain in the conducting state because the stored charge of Cl is discharged to the base of VT1 through RP1 and R1. The base of VT3 is forward-conducted from the c and e poles of VT2 through the diode VD, and the ICl is energized. The 3-pin output music signal is amplified by VT4 and then the speaker BL is sounded. Since the ICl trigger terminal 2 is connected to the positive pole of the power supply, the horn will repeatedly play the music stored in the IC1 during the timing, thereby achieving the purpose of hypnosis. When the charge stored in Cl is put to a certain extent, VTl and VT2 are turned from the on state to the off state, and VT3 is also cut off. ICl loses power and does not work, and the horn stops sounding. The potentiometer RPl is used to adjust the timing time, and the graphic data can be continuously adjusted within one hour (if the timing time is insufficient, the Cl capacity can be increased to solve). RP2 is used to adjust the volume of the speaker. The song playing speed is adjusted by RP3.