This circuit using KR142EN12 (analog – LM317 ) ic regulator that can handle load currents up to 2 amperes. For higher currents can be used IC LT1083/84/85 that each can handle currents 7/5/3A. 2000uF capacitor C3 is selected from the calculation of the current 1 Ampere. Resistor R9 is used as a current sensor to an ammeter.
In fact, not all of the thyristor passes the half-wave rectified voltage, and some of them, depending on the output voltage and load current. This can significantly reduce the power dissipated in the regulating element, especially at low output voltages and currents.
Parts list : R1 : 4K3 R2 : 18K R3 : 100 R4,R8 : 100K R5 : 1K R6 : 240 R7 : 4K7 ( Variable resistor ) R9 : 0.33 E C2 : 0.1uF C3 : 10000uF/40V C4 : 100uF/25V D1 : KY202 D2 : KD521 D3 : D311 D4 : KC147 T1 : KT814B T3 : KT209 T4 : KT 3102 IC1 : KR142EN14 (LM317)
