Electric blanket equipped with adjustable thermostatic control circuit

Circuit working principle: single-junction transistor VT2 and R' in the picture. , R4, hydrazine_, C5
, etc. form a relaxation oscillator, which provides the control electrode trigger pulse of thyristor VS; RP is
a fixed value potentiometer with small resistance and high fixed temperature. Thermistor RT (negative temperature coefficient)
is used to measure temperature. When power is first turned on, the temperature of the electric blanket is low, the resistance of RT is large, the potential of point C
is high , C, the charging time often becomes shorter, and VT2 oscillates in advance, causing the thyristor vs. As the pass angle
moves forward, the current flowing through the electric blanket is larger, making it reach the predetermined temperature setting value as quickly as possible.
When the temperature of the electric blanket is high, the RT resistance becomes smaller, the current flowing through the electric blanket becomes smaller, and the temperature gradually decreases
, thereby achieving the purpose of automatic constant temperature control.