Ohmline

Ohmline puts the everyday electronics calculations in one place: reading resistors, sizing an LED resistor, working out a voltage divider, and Ohm's law. It is made for hobby projects, repair work and learning. RESISTOR COLOR CODE • 4, 5 and 6 band resistors. Tap a band on the drawing, then pick its color. • Shows the value, the tolerance and the actual range, plus the temperature coefficient on 6-band parts. • Works the other way too: type a value such as 4.7k and see the 4-band and 5-band colors to look for. • A color chart with digits, multipliers and tolerances. OHM'S LAW WITH POWER Enter any two of voltage, current, resistance and power, and the other two are calculated. LED RESISTOR Supply voltage, LED forward voltage (typical values for red, yellow, green, blue and white are one tap away), current, and how many LEDs are in series. You get the exact resistance, the next standard value up, the real current with that resistor, the power it dissipates and the minimum wattage to buy. VOLTAGE DIVIDER Find the output voltage of a two-resistor divider, or the top resistor you need for a given output, rounded to a standard value with the resulting voltage. SERIES AND PARALLEL Totals for up to 8 resistors at once. STANDARD VALUES The nearest E6, E12, E24, E48 and E96 values for any resistance, with the error in percent. Pick the series the LED and divider tools round to. TYPE VALUES THE WAY THEY ARE PRINTED 4.7k, 4k7, 1M5, R47, 2R2, 20m for 20 milliamps, 47u. The parsed value is shown under each field, so there is no doubt what was understood. Your last inputs are remembered. Works offline, with no account, ads or tracking. Results come from ideal formulas; real components have tolerances. Take care with mains voltage and high currents.

BET