Acne treatment instrument

Circuit Operation Principle The acne treatment instrument circuit consists of a power supply circuit, a temperature control circuit, an audible alarm circuit, and a pulse heating circuit, as shown in Figure 9-24.

The power circuit is composed of a fuse FU, a power transformer T, a rectifier bridge stack UR, a filter capacitor Cl, a three-terminal voltage regulator integrated circuit lC1, and an external power socket XS.
The temperature control circuit is composed of the thermistor RT, the resistors Rl-R6, the potentiometer RP3, the capacitors C2, C3, the light-emitting diode VL2 and the relay K.
The audible alarm circuit is composed of four NAND gate integrated circuits IC3 (D1-D4), resistors R7-R13, capacitors C4, C5, transistor V2 and buzzer HA.
The pulse heating circuit is composed of a heater EH, a transistor V1, a potentiometer RP1, RP2, a resistor R14-R16, a diode VD, capacitors C6, C7, a time base integrated circuit IC4, and light-emitting diodes VLl and K.
After the AC 220V voltage is stepped down by T, UR rectified, Cl filtered, and lCl regulated, the whole machine is supplied with l2V DC voltage. After the ultra-low frequency multivibrator composed of IC4 and peripheral components oscillates, the low frequency pulse signal is output from the 3 pin of IC4, and the pulse signal is applied to the base of V1 through the normally closed contacts of R16, VL1 and K, so that V1 is intermittently turned on, EH is intermittently energized, and its temperature adjustment range is 37-45 °C.
If the heating temperature of EH exceeds the set protection temperature (45 °C) for some reason, the 10 pin of IC2 outputs a high level, so that K is energized, its normally closed contact is open, and the normally open contact When it is turned on, Vl is turned off due to the grounding of the base circuit, and EH stops heating. At the same time, the audible alarm circuit works, and the oscillating signal output by the NAND gates D1, D2 and C5, R10, and R11 (which is modulated by the oscillators composed of D3, D4, and C4, R8, and R9) After V2 is amplified, the drive HA sounds an alarm.
When using, apply the electric probe to the anus and insert it into the anus. Then power on to select the appropriate temperature.
RPl and RP2 are used to adjust the pulse heating frequency; RP3 is used to change the control temperature.
VLl illuminates when Vl is turned on, and goes out when Vl is turned off. VL2 lights up when K is pulled.
Component selection
Rl-R5 selects 1/4W metal film resistor for use.
RPl-RP3 uses a small synthetic carbon film potentiometer or variable resistor.
RT uses a negative temperature coefficient thermistor.
Cl uses aluminum electrolytic capacitors with a withstand voltage of 25V; C2, C4, C5 and C7 use monolithic capacitors or polyester capacitors; C3 and C6 select aluminum electrolytic capacitors with a withstand voltage of 16V.
VD selects 1N4148 type silicon switch diode for use.
VLl and VL2 select φ3mm LEDs.
UR uses 2A, 5OV rectifier bridge stack.
Vl selects 3DKl5OC or 2SD570 type silicon NPN transistor for use; V2 selects Sg013 type silicon NPN transistor for use.
ICl selects LM78H12 type three-terminal voltage regulator integrated circuit; IC2 selects W723B type control integrated circuit; IC3 selects CD4011 type four NAND gate integrated circuit; I call NE555 type time base integrated circuit.
HA uses a piezoelectric buzzer.
EH selects a dedicated electric heating probe of about 5W, and can also use the electric heating wire of the electric blanket (resistance is 25Ω).
K selects JRX-l3F type l2V DC relay.
T selects lOW, the secondary voltage is l5V power transformer.
The XS uses a universal power outlet.