Precharge
About the Precharge PCB
Precharge is an open source PCB design by FormulaBartonRacing, published on GitHub. It is a 2-layer board measuring 85 × 85 mm, with 61 components from 32 distinct parts.
Other key parts include the LM393 and 4N35. By type, the board carries 33 resistors, 6 test points, 6 diodes, 4 connectors, 3 ICs and 3 transistors.
From the project
Repo for 2026 circuit boards
v3.2 ----- For use with Kelly KDHE controller with 4418 uF capacitance
Main components on the Precharge
Precharge bill of materials (BOM)
61 components, 32 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | LM393 | SOIC-8_3.9x4.9mm_P1.27mm | U1 |
| 2 | 4N35 | DIP-6_W7.62mm | U3, U4 |
| 1 | CJ2310 | SOT-23 | Q1 |
| 2 | AO3400A | SOT-23 | Q2, Q3 |
| 2 | Conn_01x02 | Molex_Mini-Fit_Jr_5566-02A_2x01_P4.20mm_Vertical | J1, J2 |
| 1 | Molex MicroFit | Molex_Micro-Fit_3.0_43045-0612_2x03_P3.00mm_Vertical | J3 |
| 1 | Conn_02x03_Counter_Clockwise | Molex_Micro-Fit_3.0_43045-0612_2x03_P3.00mm_Vertical | J4 |
| 1 | KT12-1A-40L-THT | RELAY_KT12-1A-40L-THT | K1 |
| 1 | RKZE-1205S_HP | CONV_RKZE-1205S_HP | PS1 |
| 1 | R_Potentiometer_Trim | Potentiometer_Bourns_3296W_Vertical | RV1 |
| 3 | TestPoint | Pin_D1.0mm_L10.0mm | TP1, TP2, TP3 |
| 1 | TestPoint P_C | Pin_D1.0mm_L10.0mm | TP5 |
| 1 | GLV- | Pin_D1.0mm_L10.0mm | TP6 |
| 1 | Prech_Shut | Pin_D1.0mm_L10.0mm | TP7 |
| 4 | 1n4937 | D_DO-41_SOD81_P7.62mm_Horizontal | D1, D2, D4, D5 |
| 1 | P_C LED | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D3 |
| 1 | P_F LED | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D6 |
| 1 | 10uF | C_Elec_4x5.4 | C2 |
| 2 | 0.1uF | C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C3, C4 |
| 2 | 330K | R_1206_3216Metric | R1, R6 |
Show 12 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 2 | 10K | R_1206_3216Metric | R2, R3 |
| 1 | 270 | R_1206_3216Metric | R4 |
| 1 | 150 | HSA25 | R8 |
| 3 | 3.3K | R_2512_6332Metric_Pad1.40x3.35mm_HandSolder | R9, R11, R13 |
| 1 | 330 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R14 |
| 2 | 10K | R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R15, R18 |
| 2 | 1.8K | R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R16, R21 |
| 5 | 18K | R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R17, R22, R29, R30, R35 |
| 6 | 75K | R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R19, R23, R26, R31, R33, R36 |
| 6 | 8.6K | R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R20, R24, R27, R32, R34, R37 |
| 1 | 7.5K | R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R25 |
| 1 | 1.5Meg | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R28 |
Precharge design files
The KiCad project lives in the FormulaBartonRacing/Electronics repository on GitHub; these links point at the commit this page was built from.
- LayoutPrecharge/Precharge.kicad_pcb
- SchematicPrecharge/Precharge.kicad_sch
Precharge: common questions
How big is the Precharge PCB?
The Precharge measures 85 × 85 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Precharge?
61 components, from 32 distinct parts. The full bill of materials is listed on this page.
Where can I download the Precharge design files?
From the FormulaBartonRacing/Electronics repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Precharge design in my own project?
The repository has no license, so all rights stay with FormulaBartonRacing. Use it as a reference, and ask the author before reusing the design.
