Here in this circuit the voltage is supplied to the transformer through rheostat and then voltage is supplied through the mosphet p and npn transistor we know that when input is one then the output is zero in NOT gate because of the compliment so that's why some where the voltage is unregulated we combine NOT gate more in the circuit to control or make stable voltage a voltage source and resistor is applied therefore the voltage is further supplied is stable and uninterrupted and stable
