Dividers and references
Getting a specific voltage or current out of a supply you already have — including what happens once a real load is attached.
- Voltage Divider Calculator, Loaded and UnloadedEnter any three of input voltage, both resistors and output voltage to get the fourth. Add a load to see what it really does - the output resistance is R1 in parallel with R2, and anything less than ten times that will move your answer.
- Voltage Divider From Standard Resistor ValuesThe algebra gives a resistance nobody sells. This searches real E-series pairs, ranks them by output error, and shows what the tolerance does to each - which is usually the number that decides, not the ratio.
- Current Divider Calculator for Parallel BranchesCurrent entering a junction splits in proportion to conductance, so the smallest resistor takes the largest share. Handles two to six branches, and shows the dissipation in each.
- Potentiometer as a Voltage Divider, With Taper and LoadingA pot is a divider whose halves always add to the same total, so its output resistance peaks in the middle of its travel. That is why a load bends the curve instead of shifting it - and why a loaded volume control goes flat at the top.
- Zener Diode Voltage Reference and Series Resistor CalculatorSize the series resistor for a zener shunt regulator. Two worst cases pull against each other - minimum supply with full load sets the ceiling, maximum supply with no load sets the zener power - and both have to hold.
- Resistive Logic Level Shifter Calculator, 5 V to 3.3 VWhether a divider really gets one logic family into another: does the high still read high, the low still read low, nothing exceed the receiving rail - and is it fast enough for your signal. The last one is what catches people.