3.22.24 Updated to Ver 1.2files with 3 mm traces and reorganized some trace routing for better heat dissipation and low noise.

This is a reworking of the basic Variable Regulated Linear Supply schematic that can be found online. I used higher grade components like 1 watt wire wound resistors and such for mine. You can get away with lesser parts, but for a few bucks I always go with better parts. The only part that some of you may want to consider changing is the op-amp. The UA741 has a low slew rate. That is fine for my use case, but if you need this for digital or high frequency circuits than you may consider another op amp.

You must use a good heatsink for the 338's or suffer the consequences. I might have made the tracks bigger, but I got impatient with KiCAD and all the net class errors. It is designed with 3 oz copper layers and 1mm tracks. I will most likely revisit this design and use 3 mm tracks for the power circuit and add 5 volt USB out, perhaps another smoothing capacitor. The AC in has two ground pads in the middle position connected by tracks, and meant to connect chassis ground.It should put out 2-18 Volts with at least 150 watts. The transformer can do 220VA and that could allow as much as 200 watts power output but I am afraid it will overheat or melt tracks at that output level. I will update photos once I have populated and tested the design.

T1: RHA0506R000FE02 Power transformer, toroid, 225 VA, with 12V @ 18.76A / 24 VAC C 9.38A secondary

IC5: UA741CP GP Op Amp 8pin

IC1-IC4: LM338T/NOPB Linear Voltage Regulators 5 AMP ADJUSTABLE

Q1: BD140G BJT 1.5A 80V 12.5W PNP

BR1: PB5006-E3/45 45A 600V Bridge Rectifier

D1: 1N4148 Switching Diode 100V

VR1: 10K pot

R1: RS01A150R0FE12 150Ω Wire wound Resistor 1W

R2 x 4 40FR30E Wire wound Resistor 10watt .3ohm

R6: RS01A100R0FS70 100Ω Wire wound Resistor 1W

R7-8: 4.7K Resistors 1 watt

C1 .1uf tantalum capacitor

C2, C4, C6 Nichicon UFW 4700u electrolytic capacitor

C3: 10uF, Tantalum Capacitor

C7: 47uF 35V, Panansonic FC 47u Electrolytic Capacitor

SW1: 15CUFS1 AC Power Entry Modules 15A FILTERED

J1: 1452G3 Anderson Power Poles output

J2: CT4231-NI-2 / CT4231-NI-0 Red/Black binding post 35 amp

M1: (Amazon) B07M8T3T2C Panel Multi-meter 12V DC 6.5-100V 20A ( may replace with analog meter later)

Heatsinks minimum:: 578622B03200G / ATS-52290G-C2-R0 to-220 cage sinks, and adhesive 29mm for BR1

Alternatively you should use a large aluminum Case Heatsink and bend the leads of the 338's over to attach to it. Don't forget to electrically insulate the tabs.

*Case: Ebay Steel w/ Heatsinks

*12 AWG IEC power cable

Circuit Board