3-Position Slide Switch: ON-OFF-ON vs ON-ON-ON
On a 3-position slide switch, ON-OFF-ON has a center OFF position — the common is disconnected from both throws — while ON-ON-ON has no off position, so every position is a live connection. An ON-ON-ON is effectively a single-pole, triple-throw (SP3T) pattern — that is how a DPDT ON-ON-ON behaves, and a true SP3T part the same — not three independent exclusive circuits. The label alone does not tell you the wiring, so specify the truth table and the contact behavior, not the marketing words. Swiclick manufactures 3-position slide switches across the MSK, SK and SS series in SPDT, DPDT and multi-pole formats, with shorting or non-shorting contacts, rated 0.05 to 0.5 A at DC 6 to 125 V. A DPDT ON-ON-ON can be wired to behave as an ON-OFF-ON, but an ON-OFF-ON part cannot give you ON-ON-ON — so the two are not interchangeable. The difference decides one thing: whether your middle position is a dead stop or a third live state.
This is written for engineers specifying a board-level slide switch for a product, where ordering the wrong configuration means a re-spin, not a quick re-solder. The same naming applies to toggle and rocker switches, but the parts discussed here are PCB slide switches.
What does ON-OFF-ON mean?
ON-OFF-ON is a three-position switch whose center position is OFF: the common terminal is disconnected from both throws, and the two end positions each connect the common to one circuit. The middle is a true neutral.
It is the configuration you want when a design needs an “A / off / B” selection — circuit A on one side, nothing in the middle, circuit B on the other. A 3-position SPDT slide switch wired this way gives one pole, two selectable outputs, and a dead center. On a manufacturer’s catalog this is the classic three-position double-throw part; the off in the name is the whole point.
What does ON-ON-ON mean?
ON-ON-ON is a three-position switch with no off position — every position makes a live connection. On a DPDT part, the two poles do not move together: in the middle position, one pole’s common connects to one throw while the other pole’s common connects to the opposite throw. That middle state is a live, mixed connection, which is exactly what an ON-OFF-ON cannot produce.
The practical way to read a DPDT ON-ON-ON (poles P1 and P2, each with throws A and B) is in the table below.
| Position | P1 connects | P2 connects |
|---|---|---|
| Left | A | A |
| Center | A | B |
| Right | B | B |
Because the middle gives a unique P1-A / P2-B combination, a DPDT ON-ON-ON is, more correctly, a single-pole triple-throw (SP3T) pattern — and with an external jumper it can be used as one. What it is NOT is three fully independent, mutually exclusive circuits.
ON-OFF-ON vs ON-ON-ON: the difference at a glance
| ON-OFF-ON | ON-ON-ON | |
|---|---|---|
| Positions | 3 | 3 |
| Center position | OFF (common open) | Live (a third connection) |
| Use it for | Select A, neutral, then B | Three live states, no neutral |
| Typical form | 3-position SPDT/DPDT, center-off | DPDT, effectively an SP3T pattern |
| Interchangeable? | Cannot produce ON-ON-ON | Can be wired as ON-OFF-ON |
The mistake: ordering ON-ON-ON and expecting three exclusive circuits
The most common ON-ON-ON error has nothing to do with slide versus toggle. Engineers order a part labeled “ON-ON-ON” expecting three positions that each switch one common to one of three separate, exclusive circuits — and then find on the bench that two terminals stay connected across two positions. The part is doing exactly what a DPDT ON-ON-ON does; it was never going to give three exclusive throws.
True triple-throw switches that control three fully independent circuits are uncommon. So the label is the least reliable thing on the datasheet: the same three words are wired differently by different makers, and “ON-ON-ON” in particular gets ordered for a job it cannot do. Specify the truth table and the schematic for that exact part number, not the marketing words — and if a position has to be genuinely exclusive, confirm it is an SP3T, not a relabeled double-throw.
The spec the label hides: shorting vs non-shorting
There is a second parameter the position label says nothing about: what the contacts do during the move between positions — and it interacts directly with the ON-OFF-ON / ON-ON-ON choice.
A shorting (make-before-break) contact briefly connects the next circuit before releasing the previous one — useful when a signal must never drop out, but a problem if it momentarily ties two power sources or two outputs together. A non-shorting (break-before-make) contact opens first, then closes — safe for switching between sources, at the cost of a momentary open.
Here is how it ties back: an ON-OFF-ON gives you break-before-make for free between its two ends, because the center-off forces an open between them — A can never short to B on the way across. So the shorting question really bites on ON-ON-ON (and on a 2-position ON-ON), where the switch moves directly from one live state to another with no off in between. If that live-to-live transition sits between two supplies or two signal sources, the shorting behavior decides whether the changeover is clean or destructive. Swiclick slide switches are available in both shorting and non-shorting contacts — but it has to be specified per configuration, because the position name will not cover it.
How to specify the right one
Work through it in this order:
- Does the middle position need to be a true OFF/neutral? If yes, it is an ON-OFF-ON (center-off).
- Do you need three live states with no off? That is an ON-ON-ON; if any of the three must be exclusive, confirm a true SP3T, not a relabeled DPDT.
- Are you switching between two sources or supplies? Decide shorting vs non-shorting separately — the position name will not cover it.
- Then settle pole count. Whether you need one circuit or two switched together is a separate axis; see “when a slide switch circuit needs DPDT instead of SPDT” .
- Finally, verify the truth table for the exact part. Swiclick ships 1 to 50 free samples within four working days, so you can confirm the wiring of a specific configuration on your own bench before you commit a footprint.
FAQ
A DPDT ON-ON-ON can be wired to behave as an SPDT ON-OFF-ON, but the reverse is not possible — an ON-OFF-ON part has a dead center it cannot turn into a live state.
No. A DPDT ON-ON-ON is effectively an SP3T pattern, not three independent exclusive throws. Switches that truly control three separate circuits are uncommon; if you need that, specify a genuine SP3T and check the truth table
Yes — center-off and ON-OFF-ON describe the same thing: a three-position switch with an open middle. It is distinct from “center-on,” where the middle position connects the common to both throws at once.
A shorting (make-before-break) contact connects the next position before releasing the previous one; a non-shorting (break-before-make) contact opens first. The choice matters when switching between sources, and it is specified separately from the ON-OFF-ON / ON-ON-ON label.
It depends on pole count, not on the position pattern: a single-pole (SPDT/SP3T) part typically has 3 to 4 terminals, while a double-pole (DPDT) part has around 6. Always read the part’s pinout.
About Swiclick
Swiclick is a Chinese manufacturer of precision miniature switches, including slide switches across the MSK, SK and SS series in SPDT, DPDT and multi-pole formats up to 4P2T, in surface-mount and through-hole, with shorting or non-shorting contacts. Production is ISO 9001 and IATF 16949 certified. Configurations — including the position pattern and contact behavior — are quoted per application, with 1 to 50 free samples shipped within four working days and standard lead times of 7 to 15 days. See the full range on the slide switch page, or request samples or a technical datasheet for your configuration.
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Tell us your application and the specs you need, and our engineers will match a Swiclick switch and share its datasheet and pinout. Free samples ship 1 to 50 for validation before volume.
Written by Eric Chen, Application Engineer, Swiclick.
