IV Curve Tracer (Solar Cell)
This capstone project lab introduces students to the design and implementation of an automated IV Curve Tracer for solar cell characterization. Students build a custom Arduino Uno shield that utilizes high-power operational amplifiers and a 12-bit digital-to-analog converter to sweep an active load across a photovoltaic cell. Throughout the lab, students explore principles of power electronics, precision voltage and current sensing, and the thermal management required for high-current applications. By measuring the current and voltage output of a solar cell, students learn to calculate key performance metrics such as peak power point and efficiency while gaining hands-on experience with SPI communication and PC-based data visualization.
IV Curve Tracer
Solar Cell
Photovoltaics
Arduino
Power Electronics
OPA549S
Operational Amplifier
DAC
SPI
Current-Voltage Characterization
Thermal Management
Heatsink
Active Load
Electrical Engineering Capstone
PV Characterization
Signal Conditioning
Microcontroller
Precision Resistor
Uploaded by demo on 2026-07-09 · ready · Electronics · Original source ↗
Files: directions.md · Parts List.xlsx · CircuitDesignV4.pdf · REVb.zip · IVCurve4_27.ino
Readiness checks
Latest report — 2026-07-19 16:56
Readiness: IV Curve Tracer (Solar Cell)
Verdict: Ready with caveats · 2026-07-19 · est. parts cost $175–$210
The lab is implementable, but requires sourcing two critical components (the power shunt and a precision resistor) from secondary distributors as they are out of stock at DigiKey. Most significantly, the primary project archive is missing the PC-side visualization software (Installer.zip); however, research indicates these files are likely available on the project's Instructables page. The primary relay is obsolete and requires a substitute. This is a cold-check baseline report.
Action required
| Part | Problem | Recommended action |
|---|---|---|
| 1461067-7 | Obsolete; 0 stock at distributors. | Use identified Omron substitute; verify footprint against PCB before ordering. |
| HS50 R82 J | Out of stock at DigiKey. | Purchase from Arrow (200 units) or Mouser (186 units). |
| MF1/4DCT52R2002F | Out of stock at DigiKey. | Use identified Yageo substitute (in stock). |
| FK20X7S1H106K | Not For New Designs (NFND). | Use identified TDK substitute (in stock). |
| FK18X7R1H104K | Not For New Designs (NFND). | Use identified Vishay substitute (in stock). |
Parts
Integrated Circuits and Semiconductors
| Part | Spec/Package | Status | Stock | Price | Source |
|---|---|---|---|---|---|
| OPA549S | 8A Op-Amp / TO-220-11 | Active | 188 | $34.44 | DigiKey |
| MCP4921-E/P | 12-Bit DAC / DIP-8 | Active | 487 | $2.81 | DigiKey |
| 2N3904BU | NPN Transistor / TO-92 | Active | 231,511 | $0.28 | DigiKey |
| 1N4004 | Gen Purp Diode / DO-41 | Active | 178,689 | $0.14 | DigiKey |
Resistors
| Part | Spec/Package | Status | Stock | Price | Source |
|---|---|---|---|---|---|
| HS50 R82 J | 0.82 Ω, 50 W / Chassis | Out of Stock | 0 | $5.20 | Arrow |
| MF1/4DCT52R1001F | 1 kΩ 1% / Axial | Active | 79,993 | $0.10 | DigiKey |
| MF1/4DCT52R3161F | 3.16 kΩ 1% / Axial | Active | 4,560 | $0.10 | DigiKey |
| MF1/4DCT52R2002F | 20 kΩ 1% / Axial | Out of Stock | 0 | — | DigiKey |
| MF1/4DCT52R1003F | 100 kΩ 1% / Axial | Active | 9,933 | $0.10 | DigiKey |
| MF1/4DCT52R3163F | 316 kΩ 1% / Axial | Active | 4,873 | $0.10 | DigiKey |
Capacitors
| Part | Spec/Package | Status | Stock | Price | Source |
|---|---|---|---|---|---|
| UPW1J101MPD | 100 µF, 50V / Radial | Active | 5,178 | $0.74 | DigiKey |
| FK20X7S1H106K | 10 µF, 50V / Radial | NFND | 141,750 | $1.24 | DigiKey |
| FK18X7R1H104K | 100 nF, 50V / Radial | NFND | 40,230 | $0.28 | DigiKey |
| FG18C0G1H100DNT06 | 10 pF, 50V / Radial | Active | 4,525 | $0.23 | DigiKey |
Electromechanical and Hardware
| Part | Spec/Package | Status | Stock | Price | Source |
|---|---|---|---|---|---|
| 1461067-7 | Relay 24VDC 10A / 5-pin | Obsolete | 0 | — | DigiKey |
| RA-T2X-64E | Heatsink / TO-220-11 | Active | 1,338 | $6.05 | DigiKey |
| LRS-200-24 | 24V 8.8A PSU / Enclosed | Active | 945 | $24.50 | DigiKey |
| OD9225-24HSS | 24V Fan / 92mm | Active | 161 | $9.97 | DigiKey |
| Arduino Uno R3 | MCU Board | Active | Yes | $26.30 | Arduino.cc |
| PRT-00553 | 0.1" Male Headers | Active | Yes | $0.30 | SparkFun |
| 1581-0 | Banana Jack (Black) | Active | 18,687 | $3.10 | DigiKey |
| 1581-2 | Banana Jack (Red) | Active | 8,740 | $3.10 | DigiKey |
| PG9 Gland | Cable Relief / Plastic | Active | Yes | $0.20 | Pixel Paradise |
| Clear Box | 6.5 Qt Shoe Box | Active | Yes | $5.97 | Walmart |
| M3/M4 Hardware | Assorted Fasteners | Active | Yes | ~$15.00 | General |
Substitutes
| For part | Substitute | Differences | Verified | Judgment |
|---|---|---|---|---|
| 1461067-7 | G5LE-14 DC24 | Electrically identical (SPDT, 10A, 24VDC coil). | SPDT, 10A, 24VDC coil | Footprint match likely (standard sugar cube 19x15.5mm) but not verified. |
| MF1/4DCT52R2002F | MFR-25FBF52-20K | Parametric match. | 20 kΩ, 1%, 1/4W, Axial | Exact equivalent. |
| FK20X7S1H106K | FG20X7S1H106KRT06 | Parametric match. | 10 µF, 50V, X7S, Radial, 5.0mm lead spacing | Exact equivalent. |
| FK18X7R1H104K | K104K15X7RF5TL2 | Parametric match. | 100 nF, 50V, X7R, Radial, 2.5mm lead spacing | Exact equivalent. |
Instructors should verify any substitute against its datasheet before ordering.
Other dependencies
- PCB Fabrication: 2-layer board (approx. 69mm x 53mm). Gerber files (REVB) are provided and ready for manufacture.
- Firmware:
IVCurve4_27.inois not in the archive but is available on the project's Instructables page. - Software: PC-side visualization app (
Installer.zip) and source code (VSProject.zip) are missing from the primary archive. These must be retrieved from the project's Instructables (Step 12). - Libraries:
SPI.h(Standard) andDAC_MCP49xx(available via Arduino Library Manager) are required.
Watch list
- Relay K1: Footprint for the G5LE-14 substitute needs verification against the board file before bulk purchasing.
- Software Retrieval: Successful download and execution of the missing software from Instructables is the highest priority risk.
- Thermal Management: The OPA549S and HS50 resistor generate significant heat; thermal compound (Arctic Silver 5) application is critical.
Snapshot What the lab depended on when it was uploaded — the baseline the readiness checks research against.
This snapshot describes the temporal dependencies of the IV Curve Tracer lab (Electrical Engineering Capstone project). The system consists of an Arduino Uno shield utilizing high-power op-amps to sweep the load across a solar cell, powered by an external 24V supply.
Bill of Materials
Completeness is based on a reconciliation of the Parts_List.xlsx, REVB.brd element list, and CircuitDesignV4.pdf.
Integrated Circuits and Semiconductors
- Power Op-Amp (U2, U3 / Board U1, U2): OPA549S. Quantity: 2. Package: TO-220-11 (Staggered Lead). High-current capability is mandatory; these drive the load and handle up to 8A peak. Substitution is difficult due to the specialized 11-pin power package and current capacity.
- Sourcing Plan: distributor lookup: OPA549S
- 12-Bit DAC (U1 / Board U3): Microchip MCP4921-E/P. Quantity: 1. Package: DIP-8. Used for SPI-controlled voltage reference.
- Sourcing Plan: distributor lookup: MCP4921-E/P
- Small Signal NPN Transistor (Q1 / Board T1): 2N3904BU. Quantity: 1. Package: TO-92. Used to drive the relay coil. Any standard NPN small-signal transistor (VCEO ≥ 40 V, IC ≥ 200 mA) in TO-92 is compatible.
- Sourcing Plan: distributor lookup: 2N3904BU
- General Purpose Diode (D1): 1N4004 (Board) / 1N4148 (Schematic). Quantity: 1. Package: DO-41 or DO-35. Used as a freewheeling diode for the relay. Prefer the 1N4004 for robustness. Any standard power or signal diode works here.
- Sourcing Plan: distributor lookup: 1N4004
Resistors
- High Power Shunt Resistor (R6): 0.82 Ω, 50 W, 5%. Quantity: 1. Package: HS50 (Aluminum Housed, Chassis Mount). This part dissipates significant heat during the IV sweep. Must be a chassis-mount power resistor.
- Sourcing Plan: distributor lookup: HS50 R82 J
- 1% Axial Resistors (1/4W): Various values. Package: Axial 0207. These form the precision feedback and divider networks.
- 1 kΩ (R1, R2, R4, R9): 4 units.
- 3.16 kΩ (R3, R5): 2 units.
- 20 kΩ (R12): 1 unit.
- 100 kΩ (R11, R13): 2 units.
- 316 kΩ (R10): 1 unit.
- Note: The BOM lists 10 kΩ resistors (Quantity 5), but they are not used on the schematic or board.
- Sourcing Plan: distributor lookup (representative examples): MF1/4DCT52R1001F (1k), MF1/4DCT52R3161F (3.16k), MF1/4DCT52R2002F (20k), MF1/4DCT52R1003F (100k), MF1/4DCT52R3163F (316k).
Capacitors
- Electrolytic Capacitor (C1): 100 µF, 50V. Quantity: 1. Package: Radial (8mm diameter). Bulk decoupling for the 24V rail.
- Sourcing Plan: distributor lookup: UPW1J101MPD
- Ceramic Capacitors (Leaded): Various values. Package: 5.08mm lead spacing (Radial).
- 10 µF (C2): 1 unit. FK20X7S1H106K or equivalent.
- 100 nF (C3, C4, C5, C7, C8): 5 units. FK18X7R1H104K or equivalent. (C7, C8 appear on board for op-amp bypassing).
- 10 pF (C6): 1 unit. FG18C0G1H100DNT06 or equivalent.
- Sourcing Plan: distributor lookup (spec-only).
Electromechanical and Hardware
- Relay (K1): TE Connectivity 1461067-7. Quantity: 1. Package: PCB mount, 5-pin. 10A current rating mandatory for solar cell switching.
- Sourcing Plan: distributor lookup: 1461067-7
- Heatsinks (U$7, U$8): Aavid RA-T2X-64E. Quantity: 2. Specifically designed for the TO-220-11 package of the OPA549S. Non-negotiable for thermal management.
- Sourcing Plan: distributor lookup: RA-T2X-64E
- Power Supply: Mean Well LRS-200-24. Quantity: 1. 24V DC, 8.8A (approx 200W). High current is required to supply the OPA549S during peak load.
- Sourcing Plan: distributor lookup: LRS-200-24
- Enclosure Fan: Orion Fans OD9225-24HSS. Quantity: 1. 24V DC fan.
- Sourcing Plan: distributor lookup: OD9225-24HSS
- Arduino Uno: Revision 3 (A000073). Quantity: 1. The shield is designed specifically for the Uno R3 footprint.
- Sourcing Plan: retail shopping search: Arduino Uno R3
- Headers: Male break-away headers (PRT-00553). Used to connect the shield to the Arduino.
- Sourcing Plan: retail shopping search: 0.1 inch male headers
- Banana Jacks: Pomona 1581-0 (Black) and 1581-2 (Red). Quantity: 1 each. Panel mount for solar cell connection.
- Sourcing Plan: distributor lookup: 1581-0, 1581-2
- Cable Gland: PG9 plastic gland. Quantity: 1. For AC cord relief.
- Sourcing Plan: retail shopping search: PG9 cable gland
- Enclosure: Hefty Clear Box 6.5 Quart (shoe box). Quantity: 1.
- Sourcing Plan: retail shopping search: 6.5 qt plastic shoe box
- Miscellaneous Hardware: M3 PCB spacers, M4x25 machine screws, M4 lock nuts, M4 washers, nylon spacers (5/8 x 1/4 x 3/8), 14AWG wire, and thermal compound (Arctic Silver 5).
- Sourcing Plan: general web research: hardware kit for M3/M4 fasteners.
Fabrication and Software
- PCB Fabrication: The board is a standard 2-layer design. Dimensions are approximately that of an Arduino Uno shield (approx. 69mm x 53mm). Gerber files are provided (
REVB.GTL,REVB.GBL, etc.). - Firmware:
IVCurve4_27.ino. Target: Arduino Uno. Requires theSPI.hstandard library andDAC_MCP49xxlibrary. - PC Software Dependency: The lab documentation refers to an
Installer.zipfor the Windows-based visualization application and aVSProject.zipfor the source code. These files are missing from the primary archive. Without them, the PC-side plotting functionality is broken, though the Arduino will still output serial data (encoded as V+1000 and C+1000 strings). - Toolchain: Arduino IDE (any version ≥ 1.6.x). PC application requires .NET framework (version unspecified, likely 4.5+).