Tools
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Tools
Resistor colour code calculator
Pick 3 to 6 colour bands and get the value, tolerance and range at once, or type a value to get its bands.
Open calculator
Tools
Wiring board
Join real parts with wires and watch the circuit work. A first build shows you every step.
Open the wiring board
Tools
SMD resistor code calculator
Type the code on a tiny surface-mount resistor (472, 4701, 4R7, 01C) and get its value, or a value to get its code.
Open SMD calculator
Tools
SMD resistor picture generator
Type a value or a printed code like 103, 01C or 4R7 and get the chip at its real size in mm, as a picture to download.
Open the generator
Tools
Capacitor code calculator
Type the code on a capacitor (104, 103J, 4n7) and get its value, or find the code for a value, with a picture of the part.
Open the calculator
Tools
LED resistor calculator
Supply, LED colour and current in; the resistor to buy, its colour bands and wattage out.
Open LED calculator
Tools
Ohm's law calculator
Type any two of voltage, current, resistance and power; the other two are worked out.
Open Ohm's law
Tools
Transistor and regulator pinouts
Which leg is which on a BC547, 2N2222, TIP120, IRFZ44N, 7805 and more, checked against the datasheets, with a picture to download.
Open the pinouts
Practice
Resistor challenge
Read real resistors, pick one of four answers and build a streak. No calculator allowed.
Start the challenge