Pinouts & interfaces
Everything for wiring chips, boards and connectors right — per-part IC pinouts, a power/ground quick-reference table, dev-board headers, USB / Ethernet / JTAG connectors, and the ratings you need in between. Every figure is sourced from datasheets and standards.
Chip pinouts
ReferenceFind power, ground and signal pins for the common ICs — per part, or all at once.
Boards & headers
ReferencePin-by-pin layouts for the dev boards and debug headers you actually wire up.
Raspberry Pi GPIO 40-pin header + BCM numbering, with the 3.3V (not 5V-tolerant) warning. Open → Raspberry Pi Pico (RP2040) GPIO / ADC / power pins + default UART / I2C / SPI. Open → Arduino Uno Every Uno pin: PWM / SPI / I2C / interrupts. Open → Arduino Nano Every Nano pin, including the analog-only A6 / A7. Open → ESP32 GPIO GPIO functions, strapping, ADC and input-only pins in one table. Open → JTAG / SWD connector ARM 10-pin Cortex Debug and 20-pin JTAG pinouts. Open →
Connectors & cables
ReferenceWire colours, pin order, and which version does what speed.
USB Connector Pinout A / Micro / Mini / Type-C pinouts and wire colours. Open → Ethernet RJ45 Wiring T568A/B pin order + straight-through vs crossover. Open → USB Versions & Speeds USB 2.0 → USB4: signalling rates, names and connectors. Open → Ethernet Cable Categories Cat5e / 6 / 6a / 7 / 8 bandwidth, speed and distance compared. Open →
Ratings, levels & guides
Reference & learnDecode an enclosure rating, check whether two logic levels can talk, or read the deep-dive.
Pinout deep-dives
LearnFact-dense guides for the chips and parts people wire up most — with the gotchas.
NE555 pinout, specs & circuits The 555 pinout, key specs and the astable/monostable formulas with typical values. Read the guide → 74HC595 pinout & cascading What DS / SHCP / STCP do, and how to chain chips (Q7S → DS) to drive many outputs from 3 pins. Read the guide → Transistor pinout (E/B/C) Which pin is which on a TO-92 — and the trap that 2N parts are E-B-C while the BC547 is C-B-E. Read the guide → Regulator pinout (7805 / LM317) 78xx are IN-GND-OUT (tab=GND); the LM317 is ADJ-OUT-IN (tab=OUT) — not the same order. Read the guide → 74HC logic gate cheat-sheet NAND/NOR/NOT/AND/OR/XOR pinouts + truth tables — and why the 74HC02 NOR is wired output-first. Read the guide → Op-amp pinout & basics (LM358 / LM324) The LM324 power-pin trap (V+ on 4, GND on 11), plus the two gain formulas you actually use. Read the guide →
Working with passives instead? See the other topic guide →
Resistors & LEDs