Reference sheet
Connector pitches
Drawn to scale — the 2.54 vs 2.5 mm trap in one look
Connector pitches
Pitch = centre-to-centre pin spacing. Half the "why does this not fit" moments on a bench are a 2.5 mm connector meeting a 2.54 mm header: measure across eleven pins — ten gaps — and you read 25.0 or 25.4 mm.
| Family | Pitch | Seen on | Notes |
|---|---|---|---|
| DuPont / pin header | 2.54 mm (0.1″) | Breadboards, Arduino headers, jumper wires | The universal hobby pitch |
| JST-XH | 2.5 mm | LiPo balance leads, 28BYJ-48 stepper | Looks like DuPont but is 2.5 — will NOT mate reliably |
| JST-PH | 2.0 mm | Small LiPo packs, Adafruit STEMMA | The common 1S battery plug |
| JST-SH | 1.0 mm | Qwiic / STEMMA QT I2C chains | Tiny — crimping by hand is hopeless, buy pigtails |
| Grove | 2.0 mm (locking) | Seeed Grove modules | Keyed shell over a 4-pin 2 mm header |
| Screw terminal | 5.0 / 3.5 mm | Power, relays, motor drivers | Field-serviceable, no crimping |
| IDC ribbon | 2.54 mm, 2 rows | Old parallel buses, Pi GPIO breakouts | Polarity notch saves you — respect pin 1 |
