5A挺大了，3A应该可以满足你了，来一个0-30V 3A的
Input Voltage: ................ 24 VAC Input Current: ................ 3 A (max) Output Voltage: ............. 0-30 V adjustable Output Current: ............. 2 mA-3 A adjustable Output Voltage Ripple: .... 0.01 % maximum Parts List R1 = 2,2 KOhm 1W R2 = 82 Ohm 1/4W R3 = 220 Ohm 1/4W R4 = 4,7 KOhm 1/4W R5, R6, R13, R20, R21 = 10 KOhm 1/4W R7 = 0,47 Ohm 5W R8, R11 = 27 KOhm 1/4W R9, R19 = 2,2 KOhm 1/4W R10 = 270 KOhm 1/4W R12, R18 = 56KOhm 1/4W R14 = 1,5 KOhm 1/4W R15, R16 = 1 KOhm 1/4W R17 = 33 Ohm 1/4W R22 = 3,9 KOhm 1/4W RV1 = 100K trimmer P1, P2 = 10KOhm C1 = 3300 uF/50V C2, C3 = 47uF/50V C4 = 100nF C5 = 200nF C6 = 100pF C7 = 10uF/50V C8 = 330pF C9 = 100pF D1, D2, D3, D4 = 1N5402,3,4 diode 2A - RAX GI837U D5, D6 = 1N4148 D7, D8 = 5,6V Zener D9, D10 = 1N4148 D11 = 1N4001 diode 1A Q1 = BC548, NPN transistor or BC547 Q2 = 2N2219 NPN transistor Q3 = BC557, PNP transistor or BC327 Q4 = 2N3055 NPN power transistor U1, U2, U3 = TL081, operational amplifier D12 = LED diode
