2 layers105 × 44.7 mm
4 layers59.7 × 54.6 mm
Milliohm meter
gabeak2/milliohm_meter3A milliohm meter PCBA reading 10V/Ohm.
- Size
- 59.7 × 54.6 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 41
- Nets
- 20
- Pads
- 88
- Tracks, vias
- 121, 30
- Pours
- 7
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 22 Apr 2024
- Updated
- 22 Apr 2024
Overview
Milliohm meter is an open-source printed circuit board by gabeak2, from the gabeak2/milliohm_meter repository on GitHub, published under the GPL-3.0 licence. It is a 4-layer board of 59.7 × 54.6 mm with 41 parts on 20 nets, routed with 121 tracks and 30 vias.
It is built around the OPA388ID, CJ431 and AO3400A, with the BH123A and JS102011SAQN among its other parts. Its parts include 14 resistors, 8 connectors, 3 capacitors, 3 ICs and 2 diodes.
Main components
5
OPA388ID
SOIC-8-2.75V~-1.25V、1.25V~2.75V -40℃~+125℃ 1 10MHz 140dB 2.4mA 2.5V~5.5V 250nV 30pA 5V/us 5nV/℃ 60mA 60pA 7nV/√Hz@1kHz EMI filtering/RF suppression、Zero drift / auto-zero、Built-in compensation Rail-to-Rail Input, Rail-to-Rail Output SOIC-8 Precision Op Amps ROHSTexas InstrumentsPrecision Op Amps
CJ431
SOT-89-3-25℃~+85℃@(Ta) 100mA 1mA 2.5V~36V 50ppm/℃ Adjustable Parallel ±0.5% SOT-23 Voltage Reference ROHSJiangsu Changjing Electronics Technology (CJ)Voltage Reference
AO3400A
SOT-23-55℃~+150℃ 1 N-channel 1.45V 1.4W 30V 48mΩ@2.5V 5.7A 50pF 630pF 75pF 7nC@10V N-Channel SOT-23 MOSFETs ROHSAlpha & Omega SemiconductorMOSFETs
BH123A
-- Button And Strip Battery Connector ROHSMPDButton And Strip Battery Connector
JS102011SAQN
SMD-40℃~+85℃ 3.5mm 300mA 5,000 cycles 6V 9mm Black Rectangular Columnar SMD(SMT) Tab SPDT Surface Mount, Right Angle SMD Slide Switches ROHSC&KSlide Switches
README
README.mdmilliohm_meter
A milliohm meter PCBA reading 10V/Ohm, designed to be powered off of a RCR123A battery. It plugs directly into standard DVMs with 2 male banana pins with 19mm spacing, and uses kelvin sensing for resistance readings.
Parts
41| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 47k | Capacitor_SMD:C_0402_1005Metric | R5, R6, R11, R12, R15 |
| 4 | Conn_01x01 | components_2:CT3149 | J1, J2, J5, J6 |
| 4 | MountingHole_Pad | MountingHole:MountingHole_3.2mm_M3_Pad | H1, H2, H3, H4 |
| 3 | Fiducial | Fiducial:Fiducial_1mm_Mask2mm | FID1, FID2, FID3 |
| 2 | 0 | Resistor_SMD:R_0402_1005Metric | R3, R8 |
| 2 | 10 | Capacitor_SMD:C_0402_1005Metric | R9, R10 |
| 2 | 100 | Capacitor_SMD:C_0402_1005Metric | R1, R2 |
| 2 | 100nF | Capacitor_SMD:C_0402_1005Metric | C1, C2 |
| 2 | 72918 | MountingHole:MountingHole_3.2mm_M3_Pad | J7, J8 |
| 2 | AO3400A | Package_TO_SOT_SMD:SOT-23 | Q1, Q2 |
| 2 | Conn_01x02 | Connector_PinSocket_2.54mm:PinSocket_1x02_P2.54mm_Vertical | J3, J4 |
| 1 | 100.0 | Capacitor_SMD:C_0402_1005Metric | R4 |
| 1 | 1k | Capacitor_SMD:C_0402_1005Metric | R13 |
| 1 | 220 | Capacitor_SMD:C_0402_1005Metric | R7 |
| 1 | BH123A | components_2:BH123A | BAT1 |
| 1 | CJ431 | Package_TO_SOT_SMD:SOT-23 | U1 |
| 1 | DNS | Capacitor_SMD:C_0402_1005Metric | C3 |
| 1 | D_Schottky | Diode_SMD:D_SOD-323 | D1 |
| 1 | INA333xxDGK | Package_SO:VSSOP-8_3.0x3.0mm_P0.65mm | U3 |
| 1 | JS102011SAQN | Button_Switch_SMD:SW_SPDT_CK_JS102011SAQN | SW1 |
| 1 | LED_RED | LED_SMD:LED_0805_2012Metric | D2 |
| 1 | OPA388 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U2 |
Questions
How big is the Milliohm meter PCB?
It measures 59.7 × 54.6 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Milliohm meter use?
41 parts, built around the OPA388ID, CJ431, AO3400A and BH123A. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Milliohm meter KiCad files?
From the gabeak2/milliohm_meter repository on GitHub, at the commit this page was made from: the board is milliohm_meter.kicad_pcb and its schematic milliohm_meter.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Milliohm meter design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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