Pogo Pin (Test Probe) Hardware Guide

OpenFixture Pogo Pin Selection and Specification
Last Updated: February 18, 2026

📖 Overview

Pogo pins (spring-loaded test probes) are the critical contact elements in OpenFixture test fixtures. They provide reliable electrical connection to PCB test points while allowing repeated insertion/removal cycles. This guide covers pogo pin selection, specifications, installation, and maintenance for both budget-friendly and professional-grade options.

OpenFixture is designed to work with standard pogo pin series available from multiple suppliers worldwide. The fixture automatically calculates optimal compression and hole placement based on your chosen pogo pin specifications.

📐 Digole Pogo Pin Series Comparison

Digole offers four pogo pin series with different barrel diameters and lengths to suit various applications. All series use a two-part system with interchangeable probe pins and receptacles.

Source: Digole P50/P75/P100/P160 Pogo Pins

Series Specifications Table

Series	Barrel Ø	Total Length	Spring Stroke	Receptacle	Current Rating	Best For
P50	0.68mm (0.027")	16.55mm	2.65mm	R50	0.5-1.5A	Ultra-fine pitch (<0.3mm pads), micro-BGA
P75	1.02mm (0.040")	16.50mm	2.50mm	R75	1.5-3A	Most common, 0402-0805 pads, general use
P100	1.36mm (0.054")	33.30mm	6.50mm	R100	2-4A	Deep fixtures, high current, thick PCBs
P160	1.36mm (0.054")	24.50mm	4.00mm	R160	2-4A	Medium depth, high current applications

Recommended: P75 series offers the best balance of cost, availability, and performance for typical PCB testing applications.

Pogo Pin Tip Styles

Digole pogo pins use a naming convention where the 1st letter indicates tip type and the 2nd number indicates tip diameter (larger number = larger diameter).

Tip Type Reference

Code	Tip Style	Profile	Best Application	Image Reference
A	Sharp Point	Conical, very fine point	Ultra-small pads (<0.5mm), fine-pitch ICs, 01005 components	See Digole Tip Chart
B	Rounded	Hemispherical dome	Through-hole pins, general purpose, won't scratch pads
D	Flat	Flat circular face	Large pads (>1.5mm), high current, maximum contact area
E	Crown	Star/crown with center point	Most versatile, self-aligning, 0402-0805 components
F	Rounded (variant)	Smooth hemisphere	Similar to B, different geometry
G	Large Crown	Wide star pattern	Large pads, good centering, stable contact
H	Extended Crown	Long reach with crown tip	Deep recessed pads, components in cavities
J	Special Profile	Custom geometry	Specific applications (consult datasheet)
LM	Long Tip	Extended reach	Test points in confined spaces
Q	Concave	Cup-shaped	Dome-shaped solder bumps, spring pins
T	Serrated	Toothed/grooved	Penetrates oxide, reliable contact on aged boards

Tip Diameter Codes:

1, 2, 3, 4, 5: Diameter indicators (e.g., E2 is smaller than E3)
Larger numbers = larger tip diameter = more contact area = higher current capacity

Example Model Numbers:

P75-A2: P75 series, A (sharp point) tip, size 2 diameter
P75-E2: P75 series, E (crown) tip, size 2 diameter
P100-D3: P100 series, D (flat) tip, size 3 diameter

Visual Tip Profile Comparison

A (Sharp):        B (Round):        D (Flat):         E (Crown):
    /\               ___                ___            /\/\/\
   /  \             /   \            _______           \ | /
  /    \           |     |          |_______|          _\|/_
 -------          -------           -------            -------

F (Round):        G (Lg Crown):    H (Extended):     T (Serrated):
   ___              /\/\             /\               /\/\/\
  /   \            /    \           /  \             /\/\/\/\
 |     |          /      \         |    |           /\/\/\/\/\
 -------         ---------         |    |           -----------
                                   ------

Note: Actual tip profiles may vary slightly by manufacturer. Always verify dimensions with supplier datasheet.

🎯 Quick Selection Guide

Application	Recommended Series	Tip Style	Length	Cost/Point	Cycle Life
Ultra-Fine Pitch (<0.3mm pads)	P50-A2 or P50-E2	Sharp/Crown	16.5mm	$0.35	8k-30k
Prototype Testing	P75-E2 or P75-B1	Crown/Round	16-24mm	$0.30	10k-50k
Production Testing	Fixtest 100	Crown/Round	25-30mm	$3.50	100k+
High Current (2-4A)	P100-D2 or P160-D2	Flat	24-33mm	$0.45	15k-60k
Deep Fixtures (>10mm)	P100-E2 or P100-D3	Crown/Flat	33mm	$0.45	15k-60k
Small Pads (<0.5mm)	P75-A2 or P50-A2	Sharp Point	16-17mm	$0.30-35	8k-50k
Large Pads (>1.5mm)	P75-D2/D3 or P100-D2	Flat	20-33mm	$0.30-45	10k-60k
Through-Hole Pins	P75-B1	Rounded	16.5mm	$0.30	10k-50k

Series Selection by Requirement

By Pad Size:

<0.3mm pads: P50 series (ultra-fine pitch)
0.3-1.5mm pads: P75 series (most common)
>1.5mm pads: P100 or P160 series (high current capability)

By Current Requirement:

<1.5A: P50 or P75 series
1.5-3A: P75 or P160 series
2-4A: P100 or P160 series (flat tips recommended)

By Fixture Depth:

<6mm stack: P75 series (16.5mm) or P160 (24.5mm)
6-10mm stack: P160 (24.5mm) or P100 (33.3mm)
>10mm stack: P100 series (33.3mm) only

By Budget:

Lowest cost: P75 series (~$0.30/point)
Best value: P75 series (cost vs performance)
Highest performance/longevity: Fixtest 100 (~$3.50/point)

💰 P75 Series (Budget-Friendly)

Overview

The P75 series is an economical option ideal for prototypes, low-volume testing, and hobbyist projects. With prices starting at $0.16 per pin, they offer excellent value for occasional use while still providing reliable contact.

Technical Specifications

Barrel Diameter: 1.02mm (0.040")
Tip Styles: Sharp pointed, rounded, flat, crown
Total Length Range: 16.5-33.3mm (depends on model)
Spring Travel: 1.0-3.0mm typical
Current Rating: 1.5-3A (varies by tip style and contact area)
Contact Resistance: <50mΩ
Cycle Life: 10,000-50,000 cycles
Operating Temperature: -20°C to +80°C
Spring Force: 50-100g typical (varies by length)
Price: $0.16-$0.22 USD per pin + ~$0.10 for receptacle

Available Models

Model	Length	Tip Style	Tip Diameter	Best For	Price
P75-A2	16.5mm	Sharp Point	0.4mm	Very small pads (<0.5mm), fine-pitch components	$0.16
P75-B1	16.5mm	Rounded	0.8mm	Through-hole connector pins, general purpose	$0.16
P75-D2	20.0mm	Flat	1.0mm	Large pads (>1.5mm), high current applications	$0.22
P75-D3	22.0mm	Flat	1.0mm	Large pads, extra reach for thick PCBs	$0.22
P75-E2	24.0mm	Crown	~0.6mm	General purpose, 0402-0805 pads, most common	$0.22
P75-F1	26.5mm	Rounded	0.8mm	Extended reach, deep fixtures	$0.16
P75-G2	33.3mm	Large Crown	~0.8mm	Very thick fixtures, special applications	$0.22

Recommended Models for Common Applications

Best General Purpose: P75-E2

24mm length fits most fixture designs
Crown tip works well for 0402 through 0805 component pads
Good balance of reach and stability
Most versatile choice for mixed PCB designs

Best for Connectors: P75-B1

16.5mm length is compact
Rounded tip enters through-hole pins smoothly
Won't damage plated holes
Ideal for testing USB, HDMI, pin headers

Best for Fine Pitch: P75-A2

Sharp 0.4mm point for precise contact
Excellent for 0201 components and small test pads
Higher contact resistance due to small area (not for high current)
Perfect for dense BGA test points

Receptacles

P75 series uses two-part construction:

Receptacle (Holder): ~$0.10 each
- Press-fit installation into acrylic/plywood
- Barrel OD: 1.5mm typical (verify with supplier)
- Depth: Varies by model (8-15mm typical)
- Material: Brass or copper alloy
Probe Pin (Plunger): $0.16-$0.22 each (prices above)
- Spring-loaded mechanism
- Replaceable wear component
- Push-fit into receptacle

Installation

Drill holes in fixture plate (1.5mm diameter typical, verify with your receptacle specs)
Press-fit receptacles from inside of fixture plate
Insert probe pins into receptacles from outside
Test compression by closing fixture (should feel 1-1.5mm travel)

Maintenance

Replacement interval: Every 5,000-10,000 cycles
Signs of wear:
- Flattened or damaged tips
- Reduced spring force (weak contact)
- Intermittent connections
- Visible corrosion or discoloration
Tip: Buy probe pins in bulk, keep receptacles installed permanently

Suppliers

Digole Digital Solutions (P50, P75, P100, P160 series):

All Series: P50/P75/P100/P160 Main Product Page - Specifications and tip style images
P75 Series Catalog: P75 Individual Models - Direct from manufacturer
Ordering: Contact through website for bulk pricing and custom configurations
Tip Style Reference: See product page for tip profile images

Alternative Sources:

AliExpress: Search "P75 pogo pin" or "P100 pogo pin" - Bulk pricing (50-100 pcs), verify specifications
eBay: Various resellers - Good for small quantities, always verify dimensions before ordering

Cost Analysis

Per Test Point Cost: $0.26-$0.32 USD

Receptacle: $0.10
Probe pin: $0.16-$0.22

100 Test Point Fixture: ~$30 USD in pogo pins Cost per 1,000 cycles: $0.03 (assuming 10,000 cycle life)

🔬 P50 Series (Ultra-Fine Pitch)

Overview

The P50 series is the smallest Digole pogo pin, designed for ultra-fine pitch applications where the P75 series is too large. With a 0.68mm barrel diameter, these probes can test very small pads and densely packed components like micro-BGAs and 01005 passives.

Technical Specifications

Barrel Diameter: 0.68mm (0.027") - smallest in Digole lineup
Total Length: 16.55mm
Spring Stroke: 2.65mm
Receptacle: R50 (matched to 0.68mm barrel)
Current Rating: 0.5-1.5A (limited by small contact area)
Contact Resistance: <80mΩ (higher due to small tip)
Cycle Life: 8,000-30,000 cycles (smaller parts = shorter life)
Operating Temperature: -20°C to +80°C
Spring Force: 30-60g typical (lower force for delicate pads)
Price: $0.18-$0.25 USD per pin + ~$0.12 for R50 receptacle

When to Use P50

Ideal For:

Micro-BGA test points (<0.3mm pad diameter)
01005 and 0201 component testing
Ultra-high density PCBs (>1000 test points/dm²)
Fine-pitch flex circuits
Semiconductor test fixtures

Not Recommended For:

High current testing (>1A per pin)
Large pads (use P75 or P100 instead)
Rough handling environments (fragile due to small size)
General purpose testing (P75 more economical)

Available Tip Styles

Common P50 models include:

P50-A1/A2: Sharp point - for ultra-small pads
P50-B1: Rounded - less pad wear
P50-E1/E2: Crown - self-centering
P50-F1: Rounded variant

(Not all tip styles available in P50; consult supplier for current catalog)

Installation Considerations

Hole diameter: ~1.0mm (smaller than P75)
Alignment critical: Tight tolerances required
Fragile: Handle with care during installation
Recommended tool: Precision arbor press or alignment jig
Test before full assembly: Verify all probes return smoothly

Cost Analysis

Per Test Point Cost: $0.30-$0.37 USD

R50 Receptacle: $0.12
P50 Probe pin: $0.18-$0.25

Higher cost per point than P75, but necessary for ultra-fine applications

💪 P100 Series (Heavy Duty / Extended Reach)

Overview

The P100 series offers extended length (33.3mm) and larger barrel diameter (1.36mm) for applications requiring deep reach or higher current capacity. The increased spring stroke (6.5mm) provides more compliance for warped PCBs or fixtures with greater stack-up variation.

Technical Specifications

Barrel Diameter: 1.36mm (0.054") - 33% larger than P75
Total Length: 33.30mm - longest standard Digole probe
Spring Stroke: 6.50mm - excellent compliance
Receptacle: R100 (matched to 1.36mm barrel)
Current Rating: 2-4A continuous (varies by tip contact area)
Contact Resistance: <40mΩ (lower due to larger contact)
Cycle Life: 15,000-60,000 cycles
Operating Temperature: -20°C to +80°C
Spring Force: 80-150g typical (higher force for reliable contact)
Price: $0.25-$0.35 USD per pin + ~$0.15 for R100 receptacle

When to Use P100

Ideal For:

Deep fixture designs (>10mm stack height)
High current testing (2-4A per probe)
Large test pads (>2mm diameter)
Power supply testing (voltage rails, ground)
Thick PCBs (>3mm) or multiple PCB stack testing
Fixtures with significant compliance requirements

Advantages Over P75:

Longer reach accommodates deep fixtures
Higher current capacity (2-4A vs 1.5-3A)
Better compliance (6.5mm stroke vs 2.5mm)
More robust (less prone to bending)

Trade-offs:

Higher cost per probe
Requires larger holes in fixture plate (~2.0mm)
Higher spring force (may require mechanical advantage for >50 probes)
Minimum pad spacing increases (~3.5mm vs 2.5mm for P75)

Available Tip Styles

Common P100 models include:

P100-D2/D3: Flat tip - maximum current capacity
P100-E2/E3: Crown tip - general purpose
P100-B1: Rounded - through-hole testing
P100-G2: Large crown - large pad centering

Installation Considerations

Hole diameter: ~2.0mm (verify with R100 receptacle specs)
Deeper receptacle: R100 is longer, ensure adequate fixture plate thickness
Higher insertion force: Use arbor press, not manual installation
Spring force management: Consider leverage or cam mechanism for >30 probes
Pad spacing: Minimum 3.5mm center-to-center recommended

Cost Analysis

Per Test Point Cost: $0.40-$0.50 USD

R100 Receptacle: $0.15
P100 Probe pin: $0.25-$0.35

Best value for high-current or extended-reach applications

⚡ P160 Series (Medium Reach / High Current)

Overview

The P160 series provides a middle ground between P75 and P100, offering the same robust 1.36mm barrel diameter as P100 but with shorter length (24.5mm) and moderate stroke (4.0mm). Ideal when you need higher current capacity but don't require the full reach of P100.

Technical Specifications

Barrel Diameter: 1.36mm (0.054") - same as P100
Total Length: 24.50mm - between P75 (16.5mm) and P100 (33.3mm)
Spring Stroke: 4.00mm - good compliance
Receptacle: R160 (matched to 1.36mm barrel)
Current Rating: 2-4A continuous (same as P100)
Contact Resistance: <40mΩ
Cycle Life: 15,000-60,000 cycles
Operating Temperature: -20°C to +80°C
Spring Force: 70-120g typical
Price: $0.22-$0.32 USD per pin + ~$0.15 for R160 receptacle

When to Use P160

Ideal For:

High current testing with moderate fixture depth
Power delivery test points (USB-C, battery connections)
Medium-depth fixtures (5-8mm stack height)
Applications where P75 current is insufficient but P100 is too long
Cost-effective upgrade from P75 for current capacity

Comparison to P100:

Shorter (24.5mm vs 33.3mm) - more compact fixtures
Less stroke (4.0mm vs 6.5mm) - adequate for most applications
Lower cost (~$0.37 vs ~$0.45 per point)
Same current rating (2-4A)
Same barrel diameter (1.36mm) - interchangeable receptacles with P100

Available Tip Styles

Common P160 models include:

P160-D2/D3: Flat tip - high current
P160-E2/E3: Crown tip - versatile
P160-B1: Rounded - general testing
P160-F1: Rounded variant

Installation Considerations

Hole diameter: ~2.0mm (same as P100, uses similar R160 receptacle)
Interchangeable: R100 and R160 receptacles may be compatible (verify with supplier)
Spring force: Lower than P100, easier to close fixture
Space efficiency: Shorter profile allows more compact fixture designs

Cost Analysis

Per Test Point Cost: $0.37-$0.47 USD

R160 Receptacle: $0.15
P160 Probe pin: $0.22-$0.32

Best value for high-current testing in compact fixtures

🏭 Fixtest Series 100 (Professional Grade)

Overview

Fixtest Series 100 is a professional-grade test probe system designed for production environments. With 100,000+ cycle life and gold-plated contacts, these probes offer superior reliability and longevity. Higher initial cost is offset by extended lifespan in high-volume testing applications.

Technical Specifications

Series: 100 (standard industrial test probe series)
Material: Beryllium copper spring, hardened steel barrel
Contact Finish: Gold plated for low resistance and corrosion prevention
Receptacle Length: 29.6mm (S 100.00-L model)
Spring Force: Varies by model (typically 80-150g)
Cycle Life: 100,000+ cycles (high durability)
Current Rating: 3A continuous, 5A peak
Contact Resistance: <30mΩ (gold plating)
Operating Temperature: -40°C to +125°C
Precision: ±0.05mm alignment tolerance
Vibration Resistance: High (suitable for automated test equipment)
Price: ~$1.50 probe + ~$2.00 receptacle = $3.50 per test point

Key Features

Gold-Plated Contacts:

Superior electrical conductivity
Corrosion resistant
Maintains low contact resistance over lifecycle
Ideal for sensitive measurements

Beryllium Copper Spring:

Excellent spring properties
Maintains force over 100,000+ cycles
Temperature stable
High fatigue resistance

Interchangeable Probe Tips:

Multiple tip styles available
Easy field replacement
Consistent receptacle installation
Reduces maintenance downtime

Precision Alignment:

±0.05mm tolerance
Critical for automated test systems
Ensures repeatable contact
Reduces PCB pad wear

Available Models

Fixtest Series 100 offers multiple probe and receptacle combinations:

Receptacle Model:

S 100.00-L: 29.6mm length, solder-mount style
Gold-plated contact barrel
Designed for PCB mounting or fixture plate installation

Probe Styles (Interchangeable):

Crown tip: General purpose, most common
Flat tip: High current applications
Pointed tip: Fine pitch applications
Rounded tip: Through-hole testing

(Consult TME catalog for specific probe model numbers)

Installation Methods

Method 1: Press-Fit (Recommended for Fixtures)

Drill 2.0-2.2mm holes in fixture plate
Press receptacles from inside
Secure with retaining clips or adhesive if needed
Insert probes from outside

Method 2: Solder-Mount (For PCB Integration)

Design PCB with landing pads
Use fixture plate as alignment template
Solder receptacles to PCB
Mount PCB assembly to fixture

Maintenance

Replacement interval: Every 50,000-100,000 cycles
Inspection frequency: Every 10,000 cycles or quarterly
Cleaning: Isopropyl alcohol wipe (monthly in production)
Signs of wear:
- Gold plating worn through (brass visible)
- Reduced spring force
- Physical tip damage
- Contact resistance >50mΩ

Suppliers

TME (Transfer Multisort Elektronik): Fixtest S 100.00-L - European distributor
Digi-Key: Search "spring loaded test probe" or "ICT probe"
Mouser Electronics: Search "pogo pin" filter by Fixtest brand
Direct from Fixtest: Contact manufacturer for volume pricing

Cost Analysis

Per Test Point Cost: $3.50 USD

Receptacle: $2.00
Probe pin: $1.50

100 Test Point Fixture: ~$350 USD in pogo pins Cost per 1,000 cycles: $0.035 (assuming 100,000 cycle life)

ROI Calculation:

Breakeven vs P75: ~12,000 test cycles
Best choice for fixtures with >20,000 expected cycles
Consider for any production application

🏆 Alternative Professional Series

Mill-Max (USA)

Website: mill-max.com

Key Products:

Spring-loaded connectors and test probes
Very high quality American manufacturing
Price: $3-6 per test point
Excellent technical documentation and support
Variety of mounting styles (press-fit, solder, screw-mount)

Best For: Aerospace, medical, military applications requiring US-sourced components

Harwin (UK)

Website: harwin.com

Key Products:

Datamate test probe series
Automotive-grade reliability
Price: $2-5 per test point
High vibration resistance
IP67 sealed options available

Best For: Automotive, harsh environment testing

Preci-Dip (Switzerland)

Website: precidip.com

Key Products:

High-precision test and burn-in probes
Swiss manufacturing precision
Price: $4-8 per test point
Exceptional repeatability (±0.02mm)
Long life (150,000+ cycles)

Best For: Semiconductor testing, high-reliability applications

⚙️ OpenFixture Configuration

Configuration File Setup

Set pogo pin parameters in fixture_config.toml:

[hardware]
# Uncompressed length of pogo pin (measured from receptacle base to tip)
# This is the most critical parameter - measure your actual pogo pins!

# For P75-A2 or P75-B1 (16.5mm)
pogo_uncompressed_length_mm = 16.5

# For P75-E2 (24mm) - RECOMMENDED for general use
# pogo_uncompressed_length_mm = 24.0

# For P75-D2 (20mm)
# pogo_uncompressed_length_mm = 20.0

# For Fixtest S 100.00-L (29.6mm receptacle)
# pogo_uncompressed_length_mm = 29.6

# For Mill-Max or other custom probes
# pogo_uncompressed_length_mm = [measure your probe]

Automatic Calculations

OpenFixture automatically computes:

Compressed length: Based on fixture stack-up (material + PCB thickness)
Target compression: Typically 1.0-1.5mm for optimal spring force
Hole diameter: Default 0.75mm radius (1.5mm diameter) for 1.02mm barrel
Hole pattern: Exact X,Y coordinates for each test point

Compression Explained

Compression = Uncompressed Length - (Top Plate Thickness + Air Gap + PCB Thickness)

Example Calculation:

Pogo Pin: P75-E2 (24mm uncompressed)
Material: 3mm acrylic
PCB: 1.6mm
Air Gap: 0.5mm (target)

Compressed Length = 24mm - (3mm + 0.5mm + 1.6mm) = 18.9mm
Compression = 24mm - 18.9mm = 5.1mm

Note: 5.1mm is TOO MUCH compression!
Solution: Use 2-layer top plate (6mm total) for proper 1.5mm compression

OpenFixture handles these calculations automatically in the OpenSCAD model.

Validation

After generating fixture DXF files:

Check hole spacing: Minimum 2.5mm center-to-center
Verify compression: Use OpenSCAD preview
Test cut: Cut one test plate and verify receptacle fit
Dry fit: Assemble with receptacles, check alignment before inserting probes

🔧 Installation Guide

Two-Part Pogo Pin System

All recommended pogo pins use a two-part system:

Receptacle (Holder): Permanent installation in fixture
Probe Pin (Plunger): Spring-loaded, replaceable component

Installation Steps

Step 1: Prepare Fixture Plates

OpenFixture generates two top plates with identical hole patterns:

head_base: Lower guide plate
head_top: Upper alignment plate

Both have pogo pin holes at exact test point positions.

Step 2: Install Receptacles

For Press-Fit Receptacles (Acrylic/Plywood fixtures):

Identify receptacle orientation (usually wider end is top)
Position receptacle on inside of fixture plate
Use arbor press or carefully tap with non-marring mallet
Press until receptacle shoulder seats against plate surface
Verify receptacle is perpendicular to plate (not tilted)
Repeat for all test points

Tips:

Use drill jig or CNC for accurate hole placement
Start with 1.5mm holes for P75 series
If too tight: Carefully ream to 1.6mm
If too loose: Use cyanoacrylate (CA glue) around receptacle barrel

For Solder-Mount Receptacles:

Cut PCB to match fixture plate dimensions
Solder receptacles to PCB using through-hole technique
Mount PCB assembly to acrylic plate
Provides most rigid installation

Step 3: Install Probe Pins

Insert probe pin into receptacle from outside of fixture
Should slide smoothly with slight resistance
Push until pin bottoms out in receptacle
Test spring action by pressing pin (should return smoothly)
Repeat for all positions

Step 4: Alignment Verification

Close fixture (without PCB)
All probe pins should be same height ±0.2mm
Check for bent or misaligned pins
Verify smooth opening/closing action

Compression Settings

Optimal Compression: 1.0-1.5mm

This provides:

Sufficient contact force (50-100g typical)
Reliable electrical connection
Reasonable closing force
Long probe life

Troubleshooting Compression:

Symptom	Cause	Solution
Intermittent contact	Too little compression (<0.5mm)	Use thinner material or longer probes
Difficult to close	Too much compression (>2mm)	Use thicker material or shorter probes
Pins bind/stick	Misalignment	Check receptacle perpendicularity
Uneven contact	Height variation	Check fixture plate flatness

🔄 Maintenance and Replacement

Inspection Schedule

Weekly (Heavy Use):

Visual inspection for damaged tips
Test fixture closing force (should be consistent)
Check for bent or misaligned probes

Monthly:

Clean probe tips with isopropyl alcohol and lint-free cloth
Check contact resistance (use multimeter)
Inspect for corrosion or discoloration

Quarterly:

Full probe replacement if near cycle limit
Deep clean receptacles
Verify alignment with precision gauge

Probe Replacement

When to Replace:

Reached recommended cycle count
Visible tip damage (flattened, chipped, corroded)
Increased contact resistance (>100mΩ for P75, >50mΩ for Fixtest)
Weak spring force (probe doesn't return smoothly)
Intermittent connections during testing

How to Replace:

Remove old probe pin (pull straight out)
Inspect receptacle for damage or debris
Clean receptacle with compressed air
Insert new probe pin
Test spring action
Mark fixture with replacement date

Receptacle Maintenance

Receptacles last much longer than probe pins:

P75 series: 50,000-100,000 cycles for receptacles
Fixtest 100: 200,000+ cycles for receptacles

Replace receptacles when:

Physical damage (cracked, deformed)
Probe pins won't stay in place (worn retention)
Excessive play in probe pin (worn internal bore)

Spare Parts Planning

Recommended Spares:

For 100 test point fixture:

Probe pins: 20 spares (20% of total)
Receptacles: 5 spares (5% of total)
Store in sealed bag or container
Label with part number and date received

Bulk Ordering:

P75 series is often cheaper in bulk:

50 pieces: 10-15% discount
100 pieces: 20-25% discount
500 pieces: 30-40% discount

📊 Performance Comparison

Digole Series Comparison (P50 vs P75 vs P100 vs P160)

Parameter	P50	P75	P100	P160
Barrel Diameter	0.68mm	1.02mm	1.36mm	1.36mm
Total Length	16.55mm	16.50mm	33.30mm	24.50mm
Spring Stroke	2.65mm	2.50mm	6.50mm	4.00mm
Current Rating	0.5-1.5A	1.5-3A	2-4A	2-4A
Cost/Point	$0.35	$0.30	$0.45	$0.40
Cycle Life	8k-30k	10k-50k	15k-60k	15k-60k
Min Pad Size	0.2mm	0.4mm	0.8mm	0.8mm
Min Spacing	1.5mm	2.5mm	3.5mm	3.5mm
Best For	Micro-BGA	General use	Deep/High-I	Medium depth
Receptacle	R50	R75	R100	R160

Recommendations by Application:

Ultra-fine pitch (<0.3mm pads): P50 only option
General purpose (0.4-1.5mm pads): P75 best value
High current (2-4A): P100 or P160 (P160 if space limited)
Deep fixtures (>10mm): P100 only option
Budget-conscious: P75 lowest cost per point

Digole vs Professional: P75 vs Fixtest 100

Parameter	P75 Series	Fixtest 100	Winner
Initial Cost	$0.30/point	$3.50/point	P75
Cycle Life	10k-50k	100k+	Fixtest
Cost/1k Cycles	$0.03	$0.035	P75 (close)
Contact Resistance	<50mΩ	<30mΩ	Fixtest
Current Rating	1.5-3A	3A continuous	Fixtest
Operating Temp	-20°C to +80°C	-40°C to +125°C	Fixtest
Alignment Precision	±0.1mm	±0.05mm	Fixtest
Availability	Good	Excellent	Fixtest
Lead Time	2-4 weeks (China)	1-2 days (stock)	Fixtest

When to Choose Each Series

Choose P50 when:

Pad size <0.3mm (no other option works)
Ultra-high density (>1000 test points/dm²)
Micro-BGA or 01005 components
Cost is secondary to functionality

Choose P75 when:

Budget is primary concern
Pad size 0.4-1.5mm (covers 95% of applications)
Prototype or low-volume testing (<50k cycles total)
General purpose fixture
This is the default choice for most users

Choose P100 when:

Need >10mm reach (deep fixture stacks)
High current required (2-4A per probe)
Extra compliance needed (warped PCBs, thick boards)
Long-term reliability more important than cost

Choose P160 when:

High current (2-4A) but space is limited
Moderate fixture depth (5-8mm)
P75 current insufficient, P100 is overkill
Cost-effective upgrade from P75 for power testing

Choose Fixtest 100 when:

Production environment (>75k cycles total)
Automated test equipment
Gold-plated contacts required
Precision alignment critical (±0.05mm)
Extended temperature range needed
Budget allows for higher initial investment

Lifecycle Cost Analysis

Scenario: 50,000 test cycles over 2 years

Option 1: P75 Series

Initial investment: 100 points × $0.30 = $30
Replacements: 5 cycles × 20 probes × $0.20 = $20
Total cost: $50
Cost per cycle: $0.001

Option 2: Fixtest 100

Initial investment: 100 points × $3.50 = $350
Replacements: 0 (within lifecycle)
Total cost: $350
Cost per cycle: $0.007

Recommendation: P75 is more economical for <75,000 cycles

🎓 Best Practices

PCB Design for Testing

Pad Design:

Minimum size: 0.5mm diameter (prefer 0.8-1.0mm)
Remove both solder mask and paste mask
Use circular or oval pads (better than square)
Add test point silkscreen labels (TP1, TP2, etc.)

Test Point Placement:

Minimum 2.5mm spacing center-to-center
Avoid placing under tall components
Keep away from board edges (>3mm clearance)
Arrange in regular grid when possible (easier alignment)

Net Assignment:

Assign test points to same net as critical signals
Power, ground, and key signal nodes
Connector pins (if testing from opposite side)

Fixture Design

Spring Force Balance:

Total closing force = Number of pins × Force per pin
Aim for <500g total (comfortable to close by hand)
For 100 pins at 50g each = 5kg (too much!)
Solution: Use lower-force probe, or selective testing

Alignment Features:

Use dowel pins or alignment bosses
Critical for fixtures with >50 test points
Prevents PCB shifting during testing
Reduces probe tip wear

Hinge Design:

Position hinge opposite from probe concentration
Use stainless steel washers for smooth operation
Add handle or finger tab for easy opening
Consider gas spring for assisted opening (large fixtures)

Testing Strategy

Selective Testing:

Not every pad needs a probe
Focus on critical signals: Power, ground, clock, data
Use boundary scan or other methods for dense areas
Reduces probe count and closing force

Test Sequence:

Power continuity first (prevent shorts)
Ground continuity
Signal connections
Programming/boundary scan if applicable

Pass/Fail Criteria:

Define maximum contact resistance (typically 10-50Ω)
Set timeout for probe contact (pogo pins may bounce)
Use 4-wire measurement for accurate resistance reading

❓ FAQ

Q: Can I mix different pogo pin models in one fixture?

A: Yes, but not recommended. Different spring forces will cause uneven contact and difficulty closing. If necessary, group high-force pins together and add mechanical advantage (lever, cam, etc.).

Q: How do I clean pogo pins?

A: Wipe tips with lint-free cloth dampened with isopropyl alcohol (IPA). For stubborn oxidation, use a contact cleaner spray. Do not use abrasive materials (damages gold plating).

Q: My pogo pins are sticking or not returning smoothly.

A: Common causes:

Debris in receptacle - blow out with compressed air
Damaged spring - replace probe pin
Corrosion - clean with contact cleaner or replace
Over-compression - check fixture stack-up calculation

Q: Can I use pogo pins for power delivery?

A: Yes, but carefully:

P75 series: Max 1.5A per pin (use multiple pins in parallel for higher current)
Fixtest 100: 3A continuous per pin
Calculate voltage drop: V = I × R (where R = contact resistance)
Always use separate sense pins for 4-wire measurement

Q: How do I know when to replace probe pins?

A: Replace when:

Reached 50-75% of rated cycle life
Contact resistance >100mΩ (2× new spec)
Visible tip damage
Intermittent connections
Don't wait for complete failure!

Q: What's the difference between receptacle and probe pin?

Receptacle (holder): Permanent part installed in fixture plate, holds the probe
Probe pin (plunger): Spring-loaded wear component, inserts into receptacle
Think of it like a battery holder (receptacle) and battery (probe pin)

Q: Why do I have test failures on known-good boards?

A: Check:

Probe alignment - use track.dxf overlay to verify
Compression - may be too light, increase clamping pressure
Dirty probes - clean with IPA
PCB warpage - fixture may not compensate for bow
Probe wear - replace old pins

Q: Can OpenFixture work with other pogo pin brands?

A: Absolutely! Just set pogo_uncompressed_length_mm in config to match your probe. The hole diameter may need adjustment in the OpenSCAD file (default 0.75mm radius = 1.5mm diameter for P75 series).

🌐 Additional Resources

OpenFixture Documentation:

README.md - Main project documentation
fixture_config.toml - Configuration with pogo pin examples
MIGRATION_GUIDE.md - Upgrade guide

Datasheets:

Further Reading:

Test probe theory: Spring Probe Fundamentals
Contact physics: IEC 61076-4-114 (Pogo pin test methods)
Fixture design: IPC-TM-650 (Test methods for PCB testing)

Document Version: 1.0
Last Updated: February 18, 2026
Maintainer: OpenFixture Project Contributors
License: CC BY-SA 4.0

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Pogo Pin (Test Probe) Hardware Guide

📖 Overview

📐 Digole Pogo Pin Series Comparison

Series Specifications Table

Pogo Pin Tip Styles

Tip Type Reference

Visual Tip Profile Comparison

🎯 Quick Selection Guide

Series Selection by Requirement

💰 P75 Series (Budget-Friendly)

Overview

Technical Specifications

Available Models

Recommended Models for Common Applications

Receptacles

Installation

Maintenance

Suppliers

Cost Analysis

🔬 P50 Series (Ultra-Fine Pitch)

Overview

Technical Specifications

When to Use P50

Available Tip Styles

Installation Considerations

Cost Analysis

💪 P100 Series (Heavy Duty / Extended Reach)

Overview

Technical Specifications

When to Use P100

Available Tip Styles

Installation Considerations

Cost Analysis

⚡ P160 Series (Medium Reach / High Current)

Overview

Technical Specifications

When to Use P160

Available Tip Styles

Installation Considerations

Cost Analysis

🏭 Fixtest Series 100 (Professional Grade)

Overview

Technical Specifications

Key Features

Available Models

Installation Methods

Maintenance

Suppliers

Cost Analysis

🏆 Alternative Professional Series

Mill-Max (USA)

Harwin (UK)

Preci-Dip (Switzerland)

⚙️ OpenFixture Configuration

Configuration File Setup

Automatic Calculations

Compression Explained

Validation

🔧 Installation Guide

Two-Part Pogo Pin System

Installation Steps

Step 1: Prepare Fixture Plates

Step 2: Install Receptacles

Step 3: Install Probe Pins

Step 4: Alignment Verification

Compression Settings

🔄 Maintenance and Replacement

Inspection Schedule

Probe Replacement

Receptacle Maintenance

Spare Parts Planning

📊 Performance Comparison

Digole Series Comparison (P50 vs P75 vs P100 vs P160)

Digole vs Professional: P75 vs Fixtest 100