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Ohm’s Law Calculator
Find voltage, current, resistance or power. Enter any two values and get the rest instantly.
V = I × R→
Resistor Color Code
Decode 4, 5 and 6 band resistors to value and tolerance.
Brown·Black·Red→
PCB Trace Width
IPC-2221 width from current, copper weight and temperature rise.
IPC-2221→
Voltage Divider
Pick R1 and R2, get Vout. Perfect for sensors and level shifting.
R2/(R1+R2)→
LED Series Resistor
The right resistor for any LED, so it glows bright and lasts.
(Vs−Vf)/I→
555 Timer Calculator
Astable and monostable modes: frequency, duty cycle and pulse width in one place.
f = 1.44 / ((R1+2R2)C)→
Capacitor Code
Decode markings like 104 or 473 into pF, nF and µF.
104 = 100 nF→
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