According to the physical drawing, the circuit schematic is shown in the figure. The whole circuit consists of two parts: the control circuit and the heating and disinfecting circuit. Silicon Transistor are solid-state semiconductor devices with functions such as detection, rectification, amplification, switching, voltage regulation, and signal modulation. The transistor acts as a variable current switch and can control the output current based on the input voltage. Unlike ordinary mechanical switches (such as Relay and switch), transistors use electrical signals to control their opening and closing, and the switching speed can be very fast. The switching speed in the lab can reach more than 100GHz. Silicon Transistor, Power Transistor, IGBT Transistor, N-Channel Transistor, PNP Transistor YANGZHOU POSITIONING TECH CO., LTD. , https://www.cnpositioning.com
Connect the power supply SB1, 220V AC power supply, the temperature control ST temperature control ST, the over-temperature fuse FU, the diode diode VD1, the current limiting resistor R1, the Thermistor thermistor RT (PTC) to the VD2 ~ VD5 bridge The rectification and C2 filtering make the relay relay K1 pull in, and the normally open contact K1-1 is closed. At this time, the 220V AC power supply is a device that supplies power to the electronic device, also called a power supply, which supplies all the power required by the computer.
The current is divided into two paths through K1-1, one step is stepped down by capacitor C1, and VD2~VD5 is bridged to obtain 12V DC power supply DC power to maintain K1 pull-in. The other way is added to the heating and disinfecting circuit, the red disinfection indicator HL is bright, and the far-infrared quartz electric heating tube EH1 (200W) and EH2 (500W) are simultaneously heated. When the temperature of the sterilizer rises to 125 °C, the ST contact is automatically disconnected, 220V AC power is cut off, K1 is discharged, K1-1 is reset and disconnected, HL is off, and EH1 and EH2 stop heating, indicating that the disinfection is completed. If the disinfection needs to be stopped in the middle, press the stop switch SB2, the voltage across K1 is short-circuited instantaneously and lose power, K1-1 is disconnected, and the disinfection cabinet stops working immediately.
In the circuit, both FU and RT are protection components. If the circuit has a short circuit fault or abnormal temperature rise, the FU is automatically blown. If SB1 and SB2 are operated by mistake at the same time, the RT overcurrent heat is automatically disconnected for about 10s, and the normally open contact K1-1 is disconnected from the power supply for protection.