Temperature-controlled multi-point control switch circuit based on 555 integrated chip

The 555 timer has low cost and reliable performance. It only needs several external resistors and capacitors to realize pulse generation and conversion circuits such as multivibrator, monostable trigger and Schmitt trigger. It is also widely used as a timer in instrumentation, household appliances, electronic measurement and automatic control. Its various pin functions are as follows: 1 pin: external power supply negative terminal VSS or ground, under normal ground. Pin 8: External power supply VCC, the range of the bipolar time base circuit VCC is 4.5 ~ 16V, and the range of the CMOS type time base circuit VCC is 3 ~ 18V. Generally use 5V. 3 feet: output terminal V. 2 feet: low trigger end. 6 feet: TH high trigger end. 4 feet: It is the direct clearing end. 5 feet: VC is the control voltage terminal. If the external voltage is connected to this terminal, the reference voltage of the two internal comparators can be changed. When the terminal is not used, the terminal should be connected to a 0.01μF capacitor to ground to prevent interference. 7 feet: discharge end. This terminal is connected to the collector of the discharge tube and is used as a discharge of the capacitor when the timer is used.