Superb Lab Power Supply

The Superb Lab Power Supply project involves constructing a high-performance 0-30V, 3A linear regulated power supply with continuous voltage and current adjustment. Students build a hybrid system that combines a traditional analog power circuit with a custom Arduino-based digital monitoring shield. This lab teaches fundamental concepts in power electronics, including op-amp feedback loops, constant current and constant voltage modes, high-side current sensing, and 18-bit analog-to-digital conversion. Students will also gain experience with thermal management for power transistors, digital communication using the I2C protocol for character LCDs, and precision calibration techniques using Ohm's Law and standard multimeters.

Electronics Power Electronics Regulated Power Supply PSU Linear Regulator Arduino Uno Microcontroller Constant Current Constant Voltage CC/CV Op-Amp Operational Amplifier I2C Communication Current Sensing ADC Analog-to-Digital Converter Thermal Management Heatsink Calibration Overcurrent Protection OCP

Uploaded by demo on 2026-07-09 · ready · Electronics · Original source ↗

Files: 00002A.brd · 00002A.sch · 00002A.zip · BOM_Assembly.pdf · DCmeter.ino · Schematic.pdf · WiringAndParts.pdf · frontPanel.svg · manual.pdf

Readiness checks

  • complete 2026-07-09 02:04 39 searches · 0 pages
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Latest report — 2026-07-09 02:04

Readiness: Superb Lab Power Supply

Verdict: Ready with caveats · 2026-07-09 · est. parts cost $115–$135

This is a cold baseline check; no previous report exists for this lab. The design is implementable, but the primary power transistor and specific power relay are obsolete and require mandatory substitutes. Furthermore, the 24V AC-AC transformer and the high-precision Kelvin shunt are specialized components that require targeted sourcing as they are frequently out of stock or easily confused with incompatible AC-DC adapters. Firmware implementation is hindered by a dead library link in the original documentation.

Action required

Part Problem Recommended action
2SD1047 Obsolete; zero stock at major distributors. Use TIP35CG (onsemi) as a footprint-compatible substitute.
G5LE-1-VDDC12 Obsolete. Use G5LE-1 DC12 (Omron); vented (VD) suffix is not required.
WSL3637R0100FEA Out of stock at general hobbyist distributors. Source from specialized vendors (e.g., Future Electronics or TTI).
24V AC Transformer High risk of purchasing incorrect AC-DC adapter. Ensure transformer is 24V AC-AC (e.g., Ensign L100-2-524). DC input is forbidden.
LiquidCrystal Library Original Bitbucket link is dead. Redirect students to the GitHub mirror: github.com/fmalpartida/New-LiquidCrystal.

Parts

Integrated Circuits and Semiconductors (Digital Meter Board)

Part Spec/Package Status Stock Price Source
IC1: MAX44284FAUT+ Current Amp / SOT23-6 Ready 2,773 $3.66 DigiKey
IC2: MCP3422A0-E/SN ADC / SOIC-8 Ready 4,069 $3.72 DigiKey
IC3: MCP6061T-E/OT Op-Amp / SOT23-5 Ready 574 $0.84 DigiKey
Q1, Q2: BC817-25LT3G NPN / SOT23 Ready 3,187 $0.17 DigiKey
D3: BAT54 Schottky / SOT23 Ready 424,390 $0.14 DigiKey
Z1: 824501361 TVS 36V / SMA Ready 4,611 $0.29 DigiKey

Integrated Circuits and Semiconductors (Analog PSU Kit)

Part Spec/Package Status Stock Price Source
U1, U2, U3: TL081CP Op-Amp / DIP-8 Ready 10,105 $0.70 DigiKey
Q1: 9014 NPN / TO-92 Ready >100 $0.08 Addicore
Q2: 2SD882 NPN / TO-126 Ready 8,181 $2.50 DigiKey
Q3: 9015 PNP / TO-92 Ready >100 $0.08 Addicore
Q4: 2SD1047 NPN Power / TO-3PL Obsolete 0 — —
D1-D4: 1N5408 Rectifier / Axial Ready 41,798 $0.35 DigiKey
D5-D10: 1N4148 Signal / Axial Ready 1M+ $0.10 DigiKey
D7, D8: 1N4733A 5.1V Zener / Axial Ready 85,582 $0.26 DigiKey
D11: 1N4004 Rectifier / Axial Ready 128,112 $0.14 DigiKey
D12: LED 5mm T1-3/4 not checked — — —

Passives (Digital Meter Board)

Part Spec/Package Status Stock Price Source
R4: WSL3637R0100FEA 0.01 Ω Shunt / 3637 At risk >100 $1.05 Future Elec
Resistor Kit 0603 Variety Ready >100 $39.95 Adafruit
Capacitor Kit 0603 Variety Ready >100 $39.95 Adafruit

Passives (Analog PSU Kit)

Part Spec/Package Status Stock Price Source
Power Resistor 0.47 Ω 5W / Radial Ready 605 $1.26 DigiKey
RV1: 3296W-104 100k Ω Multi-turn Ready >100 $2.38 Mouser
Panel Potentiometers 10k Ω Linear Ready >100 $0.95 Adafruit
Axial Resistor Kit 0.25W Variety Ready >100 $9.95 RobotShop
Electrolytic Kit 50V Minimum Ready >100 $5.99 ShillehTek
Film/Ceramic Kit Various Ready >100 $14.95 Electronix Exp

Electromechanical and Chassis Hardware

Part Spec/Package Status Stock Price Source
K1: G5LE-1-VDDC12 Power Relay / DIP-5 Obsolete 0 — —
Arduino Uno R3 Microcontroller Ready >100 $4.99 Micro Center
20x4 I2C LCD Character Display Ready >100 $4.50 Elecrow
Transformer 24V AC / 100VA Ready >100 $25.67 PowerVolt
Heatsink for Q4 TO-247 Large Ready >100 $7.60 DigiKey
Enclosure Aluminum Box Ready >100 $7.99 eBay
Terminal Block 4-way 5.08mm Ready 144 $1.94 DigiKey
Molex Connectors KK 254 Series not checked — — —
Pin Headers 0.1 inch not checked — — —
Binding Posts Banana Sockets not checked — — —
Cooling Fan 24V DC Ready >100 $5.45 CoolerGuys

Substitutes

For part Substitute Differences Judgment
2SD1047 TIP35CG TO-247 package; 25A rating exceeds original 12A. Recommended.
G5LE-1-VDDC12 G5LE-1 DC12 Suffix difference; identical footprint and coil. Recommended.

Verify any substitute against its datasheet before ordering.

Other dependencies

  • Firmware: DCmeter.ino target for Arduino Uno (not checked).
  • Library Dependency: LiquidCrystal_I2C. Original link is dead; use GitHub mirror at github.com/fmalpartida/New-LiquidCrystal.
  • Fabrication: 2-layer PCB (not checked).
  • Calibration: Requires manual adjustment of RV1 until output is 0V at minimum setting.
  • Input Constraint: 24V AC only; DC input is forbidden by design.

Watch list

  • WSL3637R0100FEA: This 4-terminal Kelvin shunt is specialized and frequently has zero stock at major distributors (DigiKey/Mouser).
  • 24V AC-AC Transformer: Retailers often provide AC-DC power bricks when "24V transformer" is searched. Chassis-mount AC-AC units must be manually verified.
Snapshot What the lab depended on when it was uploaded — the baseline the readiness checks research against.

This snapshot describes the hardware and software dependencies for the "Superb Lab Power Supply," a 0-30V, 3A regulated supply. The design is a hybrid consisting of a standard analog power supply circuit (often sold as a DIY kit) and a custom "DC Meter" Arduino shield that provides digital monitoring, I2C display, and relay-based OVP/OCP protection.

Bill of Materials

This list reconciles the 00002A "DC Meter" board (primary authority for monitoring logic), the Analog PSU kit documentation, and the assembly manifests.

Integrated Circuits and Semiconductors (Digital Meter Board)

  • IC1: MAX44284FAUT+
    • Quantity: 1
    • Package: SOT23-6
    • Description: High-side current-sense amplifier. Must be the "F" gain variant (50V/V).
    • Sourcing Plan: distributor lookup: MAX44284FAUT+T
  • IC2: MCP3422A0-E/SN
    • Quantity: 1
    • Package: SOIC-8
    • Description: 18-Bit Analog-to-Digital Converter with I2C interface.
    • Sourcing Plan: distributor lookup: MCP3422A0-E/SN
  • IC3: MCP6061T-E/OT
    • Quantity: 1
    • Package: SOT23-5
    • Description: High precision, rail-to-rail Op-Amp.
    • Sourcing Plan: distributor lookup: MCP6061T-E/OT
  • Q1, Q2: BC817 NPN Transistor
    • Quantity: 2
    • Package: SOT23
    • Constraint: The board file specifies -16 gain grade; the PDF BOM specifies -25 gain grade. Any BC817 variant is likely functional for the relay drive.
    • Sourcing Plan: distributor lookup: BC817-25LT3G
  • D3: BAT54 Schottky Diode
    • Quantity: 1
    • Package: SOT23
    • Sourcing Plan: distributor lookup: BAT54
  • Z1: TVS Diode (Uni-directional)
    • Quantity: 1
    • Package: SMC (Surface Mount)
    • Constraint: The board value is 824501401 (40V), while the BOM specifies 824501361 (36V). Given the 30V output rail, the 36V or 40V version is required for protection.
    • Sourcing Plan: distributor lookup: 824501361

Integrated Circuits and Semiconductors (Analog PSU Kit)

  • U1, U2, U3: TL081 Op-Amp
    • Quantity: 3
    • Package: DIP-8
    • Substitution: Standard JFET-input op-amp.
    • Sourcing Plan: distributor lookup: TL081CP
  • Q1: 9014 NPN Transistor
    • Quantity: 1
    • Package: TO-92
    • Sourcing Plan: retail shopping search: 9014 NPN transistor
  • Q2: 2SD882 NPN Transistor
    • Quantity: 1
    • Package: TO-126
    • Sourcing Plan: distributor lookup: 2SD882
  • Q3: 9015 PNP Transistor
    • Quantity: 1
    • Package: TO-92
    • Sourcing Plan: retail shopping search: 9015 PNP transistor
  • Q4: 2SD1047 NPN Power Transistor
    • Quantity: 1
    • Package: TO-3PL / TO-247
    • Constraint: High power dissipation. Must be mounted on a large heatsink.
    • Sourcing Plan: distributor lookup: 2SD1047
  • D1, D2, D3, D4: 1N5408 Rectifier Diode
    • Quantity: 4
    • Package: Axial DO-201AD
    • Sourcing Plan: distributor lookup: 1N5408
  • D5, D6, D9, D10: 1N4148 Signal Diode
    • Quantity: 4
    • Package: Axial DO-35
    • Sourcing Plan: distributor lookup: 1N4148
  • D7, D8: 5.1V Zener Diode
    • Quantity: 2
    • Package: Axial (e.g., 1N4733A)
    • Sourcing Plan: distributor lookup: 1N4733A
  • D11: 1N4004 Rectifier Diode
    • Quantity: 1
    • Package: Axial DO-41
    • Sourcing Plan: distributor lookup: 1N4004
  • D12: LED
    • Quantity: 1
    • Package: 5mm T1-3/4
    • Description: Constant current mode indicator.

Passives (Digital Meter Board)

  • R4: Current Shunt Resistor (0.01 Ω)
    • Quantity: 1
    • Package: 3637 (Surface Mount)
    • Constraint: 1% tolerance, high precision Kelvin-connection shunt.
    • Sourcing Plan: distributor lookup: WSL3637R0100FEA
  • Commodity Resistors (0603, 5% or 1%)
    • Values: 1.8k Ω (x1), 470 Ω (x8), 1.8M Ω (x1), 100k Ω (x2), 4.7k Ω (x7).
    • Sourcing Plan: retail shopping search: 0603 resistor kit
  • Commodity Capacitors (0603)
    • Values: 2.2nF NP0 (C1), 10µF X5R (C2), 100nF X7R (C3, C4, C5, C6, C7).
    • Sourcing Plan: retail shopping search: 0603 capacitor kit

Passives (Analog PSU Kit)

  • Power Resistor: 0.47 Ω 5W
    • Quantity: 1
    • Package: Radial Ceramic Block
    • Sourcing Plan: distributor lookup (representative): SQP500JB-0R47
  • Precision Multi-turn Potentiometer: 100k Ω
    • Quantity: 1
    • Package: 3296W type (top adjust)
    • Sourcing Plan: retail shopping search: 3296W-104 potentiometer
  • Panel Potentiometers: 10k Ω Linear
    • Quantity: 2
    • Description: Used for Voltage and Current adjustment.
    • Sourcing Plan: retail shopping search: 10k linear potentiometer panel mount
  • Commodity Axial Resistors (0.25W unless noted)
    • Values: 2.2k Ω 1W (x1), 82 Ω (x1), 220 Ω (x1), 4.7k Ω (x1), 10k Ω (x5), 27k Ω (x2), 2.2k Ω (x2), 270k Ω (x1), 56k Ω (x2), 1.5k Ω (x1), 1k Ω (x2), 33 Ω (x1), 3.9k Ω (x1).
    • Sourcing Plan: retail shopping search: axial resistor kit
  • Electrolytic Capacitors (50V minimum)
    • Values: 3300µF (x1), 47µF (x2), 10µF (x1).
    • Sourcing Plan: retail shopping search: 50V electrolytic capacitor kit
  • Film/Ceramic Capacitors
    • Values: 0.1µF 104 (x1), 0.22µF 224 (x1), 100pF 101 (x2), 330pF 331 (x1).
    • Sourcing Plan: retail shopping search: ceramic disc capacitor kit

Electromechanical and Chassis Hardware

  • K1: Power Relay
    • Quantity: 1
    • Package: Through-hole (DIP-5 style)
    • Description: 12VDC coil, SPDT.
    • Sourcing Plan: distributor lookup: G5LE-1-VDDC12
  • Arduino Uno R3
    • Quantity: 1
    • Description: Host microcontroller for the digital meter shield.
    • Sourcing Plan: retail shopping search: Arduino Uno R3
  • 20x4 I2C LCD Display
    • Quantity: 1
    • Description: Character LCD with I2C backpack. Address defaults to 0x3F or 0x27.
    • Sourcing Plan: retail shopping search: I2C LCD 2004 module
  • Transformer
    • Quantity: 1
    • Spec: 24V AC secondary, >90W power rating.
    • Sourcing Plan: general web research: 24V 4A power transformer
  • Heatsink for Q4
    • Quantity: 1
    • Spec: Large "considerable size" fins required for linear regulation dissipation.
    • Sourcing Plan: retail shopping search: TO-247 large aluminum heatsink
  • Enclosure
    • Quantity: 1
    • Description: Aluminum enclosure recommended.
    • Sourcing Plan: retail shopping search: aluminum project box for power supply
  • Connectors
    • Terminal Block: MKDSN1,5/4-5,08 (4-way, 5.08mm pitch).
    • Molex Connectors: KK 254 series or equivalent 2, 3, and 4-pin headers (X2-X7).
    • Pin Headers: 0.1 inch standard headers for Arduino interface.
    • Binding Posts: 4pcs Banana sockets (Red, Black, Green).
  • Cooling Fan
    • Quantity: 1
    • Spec: 24V DC fan.
    • Sourcing Plan: retail shopping search: 24V 40mm or 60mm DC fan

Software and Firmware

  • Firmware: DCmeter.ino target for Arduino Uno.
  • I2C Addresses: LCD at 0x3F, MCP3422 at 0x68.
  • Library Dependency: LiquidCrystal_I2C. The source code references a specific Bitbucket download for "New LiquidCrystal" by fmalpartida. If this link fails, standard Arduino I2C LCD libraries may require pin mapping adjustments in the constructor.
  • Calibration: The firmware uses internal scaling factors for the 18-bit ADC. RV1 on the analog board must be adjusted until the output is exactly 0V when the voltage potentiometer is at minimum.

Fabrication Notes

  • PCB Dimensions: 53.34 mm x 53.34 mm (approximately 2.1 x 2.1 inches).
  • Layer Count: 2 layers (Top/Bottom).
  • Thermal Management: The power transistor Q4 (2SD1047) handles high wattage; it must be insulated from the heatsink using a ceramic insulator sheet (TO-264 style) if the heatsink is grounded to the chassis.
  • Input Constraint: This circuit requires 24V Alternating Current (AC) input. DC input is explicitly forbidden by the manual.