This 0-60V variable voltage regulator power supply circuit is designed to supply the output voltage to zero volt, without a transformer with a secondary winding two coils. We can use the well-known IC is LM723. Or if you want to pressure is higher, use a number L146. Although is known less. But enough buy them. Depending on the needs of the builder
How it work
This circuit has the output current limit section and continuously adjusted. The table below shows the values of used equipment. To change the properties of a three circuits model for the maximum output voltage to 30 volts, 40 volts and 60 volts. The circuit that show as size of 40 volts / 0.8 Amps. which we use the L146 is main, due to the output voltage can be higher than the number LM723. But not equal to the lowest pressure, is about 2 volts. The network resistors are R3, R4, and R5, R6 use for adjusted the offset of this voltage, makes the output can fine to zero volts with P2. And by these resistors will help we have the voltage control at pin 4 and pin 5 of IC1 constant and not stop working. Although the the circuit input voltage drops below the required level.
This the circuit design,there is special driver T3. When the output voltage is loaded lower than a voltage regulated, the volts at pin 4 also will lower pin 5 , the IC1 will offset, with increased the volt output at pin 9, but pin 9 is connected to ground by R7 and D2 that as limit the maximum voltage.
Although the the voltage can not be increased, but the current is increasing. Therefore, using R7 limits the current to 6 mA. This current flows through the IC1 from pin 11 and to pin 9. As a result, the voltage drop across the P1, also drive T2. If the voltage is increased, T3, it will take less current. At spindle of P1 is connected to T1, to control the current limiting circuit.
When a drop across voltage R1 over 0.6 volts, the P1 will be short circuit by R1 and T3 stop conducted current. If the circuit limited current out away, the voltage drop the P1 is constant to 1.2 volts (voltages diode D1 and pin B -pin E of T2) and this some volts is mixed to a drop volts R1 to driver transistor T1 get a few voltage and mix some one of P1. If it over to 0.6 volts when T1 will be conduct current makes T3 stop running as limiting current just only, as a result we can control the output current from zero to miximum.
Notice that, LM723 can use maximum only 36 volts but L146 resist up to 80 volts. And if will use L146 should use a input voltage from the transformer that provide higher volts than 24V but under 48V. And must change T3 to Number :2N3442 because 2N3055 resisted volts only on 60V
The table below is shown value of parts that use in changing the special feature circuit of 3 model, depends on the size of voltage. But whether it be the voltage and current. Do not get T3 be losing power up to 40 watts. Wherefore the maximum output current of the 40 volts form, will supply of 0.8 amps. Which can use two 2N3055 transistors parallel together to supply output current up 2 times. And must use the transformer 2 ampere too.