Tools you might need next
Decode resistor color bands to resistance value in ohms or find the correct color bands for a target resistance and tolerance.
Calculate current-limiting resistor value and wattage for LED circuits from supply voltage, forward voltage, and desired current.
Calculate RC circuit charge and discharge time constants, voltage curves, and time to reach a target voltage level in seconds.
Output is the fraction of input dropped across R2 in series with R1.
Vout = Vin × R2 / (R1 + R2)A parallel load RL appears in parallel with R2, lowering Vout unless divider impedance is much lower than load.
Series current is Vin / (R1 + R2). Choose resistor values to limit quiescent current and wattage.
Updated: July 2026
Pick R1 and R2 so max signal stays below microcontroller reference with margin.
Set mid-rail Vref from a stable 5 V supply.
Calculate divider bias with base current loading accounted for.
Motors need far more current than a passive divider can supply. Use a driver or regulator.
Treat ADC input as a load on R2 or buffer with an op-amp follower.
Design or analyze resistor dividers for sensors and references. Enter Vin and resistor values to get Vout, or solve for R1/R2 from a target output.