Thyristor voltage-regulated drying room temperature control circuit 2

The characteristic of this circuit is that it does not use a transformer. A single-junction transistor is used to trigger three
thyristors a respectively, although the maximum phase shift range of this circuit is only 120. , but the conduction angle of the thyristor is still 60. , that is to say, the
voltage regulation range is from iso to siov.
By adjusting the potentiometer RP2, the conduction angles of the three thyristors can be changed, thereby changing the electrical resistance at both ends of the electric heater 2g EH.