The editor's part panel files every part under exactly one category. Here is what each one holds, with a few of the parts in it and where to read more. To find one part by name, type in the panel's search box; see finding a part.
Basics
LED, resistor, capacitor, clock and lamp. The parts a first circuit is made of. The clock is a square wave at a frequency you set, so a circuit with no processor in it still has something moving.
Boards
The Arduinos, the ESP32 and ESP8266 boards, the Raspberry Pi Pico and Pico W,
the Raspberry Pi 4, Pi 5 and Zero 2 W, the STM32 boards, the XIAOs, the
micro:bit and the bare ATtiny85. Each runs real firmware on our own CPU core,
except the Raspberry Pis, which run a Python main.py. See
the boards.
Inputs
Pushbuttons, slide, toggle and DIP switches, an emergency stop, joysticks, rotary encoders, keypads, potentiometers, arcade buttons and levers, a PS/2 keyboard, touch pads, a fingerprint reader and a coin acceptor. Everything a person presses, turns or tips. The pushbutton models contact bounce, which is why a debounce lesson here can show the problem rather than describe it. See the parts games are made of and keypads.
Sensors
The largest category: light, temperature, humidity, pressure, distance, motion, magnetic field, current and voltage, gas, sound, water and soil. Each has a slider or a click on the canvas for the thing it is sensing.
Many are a resistor or a switch in disguise, and what each one really is is worth five minutes. Others talk a protocol: the DHT22 is timed on one wire (signals you time), and the BME280, MPU6050 and their kind are I2C chips (two wires, several chips). The kit boards have their own pages: the MQ gas sensors, switch modules, comparator modules and analog modules. Two read the body or the room as a signal: the AD8232 heart monitor and the INMP441 I2S microphone.
Outputs
Things that move, light up or make a noise: buzzers and speakers, LEDs and WS2812 strips, servos, DC motors, steppers and their drivers, relays, pumps, fans and solenoids, a thermal printer, robot kits and the game cabinets. A board pin cannot drive a motor, so the drivers are here too; see driving a motor, a stepper is four coils and a table and relay boards.
The 12 V parts: the TB6600 stepper driver, a brushless motor on an ESC, a linear actuator, water pumps, solid-state relays, a Peltier module, an electromagnet, a PC fan, power LEDs and a siren. Also here: the infrared LED and KY-005 and the MAX98357A I2S amplifier.
Displays
Seven-segment digits and their driver chips, LED matrices, character LCDs (on their own pins or behind an I2C backpack), OLEDs, color TFTs from the ST7735 to the 3.5 inch ILI9488 and 4 inch ST7796, and e-paper. Each decodes its datasheet's protocol off the pins, and the panel on the canvas repaints from what the part was sent.
Logic
An ideal gate and inverter as teaching parts, the bit parts for building a computer (bits, the computer parts), and the real chips: the 74HC family, more 74HC gates and the CD4000 gates, the counters, decoders and shift registers, plus port expanders, multiplexers, a level shifter and an EEPROM.
The chips have VCC and GND as real pins and do nothing until they are wired. Unpowered, every output is high impedance, which is the commonest reason a logic circuit looks dead.
Timers and analog
The 555, op-amps and comparators (op-amp chips, comparator chips), analog switches, monostables, transistors, MOSFETs, diodes, an optocoupler, resistor networks and the inductor. The bench instruments live here too: the signal and function generators, oscilloscope, logic analyzer, multimeter, bench and dual power supplies, frequency counter, logic probe and component tester. See the bench instruments and the logic analyzer.
Clocks and links
Real-time clocks, the PCA9685 servo driver, the HC-05 and HC-06 serial bridges (said plainly), the MAX485 and MAX232 line drivers, the SIM800L and SIM900A GSM modems, the infrared remote and receiver, the MP3 player, the RFID and NFC readers, the microSD card, GPS, the nRF24L01 and LoRa radios, and the TCA9548A I2C multiplexer.
Power and wiring
VCC and GND, batteries, the 12 V DC jack, USB power, a voltage source, AC mains and a transformer, a solar panel, the TP4056 charger, linear regulators, the LM317, the LM2596 buck converter and other buck and boost modules, the MB102 breadboard supply, screw terminals, and the full and half breadboards. The breadboard is a real 0.1 inch grid with the rails down each side and a 0.3 inch center channel for DIP chips.
Every part has a page
/parts is grouped by these same ten families, with a count of the parts in each. Open any part's page from there to see what it does, how it is wired and the projects that use it.