The invention relates to a
voltage stabilizing circuit of an
alternating current voltage stabilizer. The
voltage stabilizing circuit of the
alternating current voltage stabilizer comprises a power input, a power circuit and a voltage stabilizing circuit, wherein the power circuit and the voltage stabilizing circuit are connected in sequence; the voltage stabilizing circuit comprises a voltage
signal detection circuit and a voltage stabilizing
control circuit; the voltage stabilizing
control circuit comprises capacitors C9 and C12, an
operational amplifier U1A, resistors R4, R6, R10 and R11, transistors Q1 and Q2 and a
direct current motor connecting terminal J2; the voltage
signal detection circuit comprises resistors R5, R7 and R8, a voltage stabilizing
diode Z3, a
diode D6 and an adjustable
resistor W1. According to the voltage stabilizing circuit of the
alternating current voltage stabilizer, voltage judgment is realized by using a
comparator with hysteretic characteristic, so under-voltage and over-voltage adjustment can be accurately realized; the turning direction of a
direct current motor is controlled by using the double transistors in a complementary working mode; the entire circuit is simple in design, high in reliability and low in cost.