Resistance combination search
Name a resistance. Resistora returns the resistors that reach it.
You need a resistance no single resistor gives you. Resistora searches the sixteen resistance circuits — two to four resistors wired in series and parallel — filling their slots either from the kit you own or from a whole IEC 60063 series, ranks everything it finds by error, and hands you the three that land closest.
- resistance circuits
- 16
- resistors per combination
- 2–4
- targets in range
- 0.1 Ω–100 MΩ
- closest combinations shown
- 3
Where to start
Combination Search answers out of a kit and E-Series Search out of a series, and the two are never mixed in one search. Circuit Calculator runs the other way: given the resistors, it returns the number they make.
Combination Search
The resistors are already in your drawer
How many of a resistor you own is the ceiling on how many slots it may fill: one 1 kΩ in the drawer never comes back as two.
Search your kitE-Series Search
You have not ordered anything yet
One value may fill every slot, because a catalogue never runs out, and the series you buy from caps how many resistors a combination may use.
Search a seriesCircuit Calculator
The resistors are already decided
Fill every slot of a circuit and it tells you what that circuit produces, then carries the value into either search.
Work out a circuit
What it is for
You need a resistance you do not have, and the question is what you can build to reach it. The answer is a circuit of two to four resistors, unless a single part already sits closer, and then you are told so.
Given the value, it returns the parts
A resistor calculator is handed the parts and reports the value they make. Resistora runs backwards: you state the value, and what comes back is the arrangement — which parts in which slots, wired which way. That is why it has to know which resistors are on the table.
Sixteen circuits, searched exhaustively
Two circuits wire two resistors, four wire three, ten wire four, and every one in the range you ask for is searched on every run, none sampled and none skipped. Circuits that divide a source voltage down to an output voltage answer a different question; they will be a tool of their own, and that tool is not built.
What a combination has to beat
A combination is only worth soldering if it beats the one part you could have used instead. Searching a kit, Resistora says so whenever a resistor you already own is at least as close, names it, and sends you to that one. Searching a series, the nearest standard value and its error stand above every list, won or lost.
Free, signed out, and computed on your own machine
Every tool is free and works signed out. The search runs inside your browser on background threads, with no calculation server behind it. An account changes nothing about a search; it keeps your kit, so the drawer you typed in once follows you to your next device.