Component Library
The parts you'll meet most often in electronics: drawings and real photos, through-hole and SMD versions, pinouts and things to watch out for.

Resistor
RLimits current, divides voltage.

Capacitor
CStores electric charge and smooths voltage.

LED
DA diode that lights up when current flows.

Diode
DPasses current in one direction.

Transistor
QControls a large current with a small one.

Integrated circuit (IC)
UA whole circuit in one package.

Potentiometer and trimpot
RV / VRA resistor whose value changes as you turn it.

NTC thermistor
RT / NTCA resistor whose resistance falls as it warms.

LDR (light-dependent resistor)
LDRA resistor whose resistance falls as light increases.

Varistor (MOV)
RV / VDRA protection part that clamps overvoltage.

Inductor
LOpposes changes in current and stores energy in a magnetic field.

Transformer
T / TRSteps AC voltage up or down and isolates the two sides.

Relay
K / RLA switch that turns a big circuit on and off with a small current.

Zener diode
D / ZDA diode that conducts in reverse at a fixed voltage.

Bridge rectifier
BD / BRFour diodes in one package that turn AC into DC.

MOSFET
QA voltage-controlled power switch.

Linear regulator (78xx, LM317)
U / ICMakes a steady output voltage from a varying input.

Optocoupler
U / OCIsolates two circuits by carrying the signal with light.

Fuse
FA part that melts on overcurrent to protect the circuit.

Crystal (quartz)
X / YGives processors an accurate clock signal.

Buzzer
BZA small part that makes sound: active and passive types.