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I need to control a latching relay but I don't need to change its state alternatively with one single input. I need to control its state with two separate pushbutton: "open" and "close". Does it exists?

If the relay is open and I push "open" nothing should happen and the same for "close".

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  • \$\begingroup\$ Voting to close this because this is a shopping type question and not within the normal electronics design type postings. \$\endgroup\$ – Michael Karas Jun 4 '16 at 18:00
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    \$\begingroup\$ Did you even attempt to look for dual coil latching relays? \$\endgroup\$ – Michael Karas Jun 4 '16 at 18:01
  • \$\begingroup\$ Maybe this design has a common name and this can help me find it \$\endgroup\$ – Tobia Jun 4 '16 at 18:01
  • \$\begingroup\$ There are several different types of latching relays, and in order not to waste our lives on guesswork we need to know which relay you're talking about. Can you post a data sheet or, at the very least, a link to it or the relay's part number and manufacturer, please? \$\endgroup\$ – EM Fields Jun 4 '16 at 18:01
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    \$\begingroup\$ @Michael Karas I don't agree this is really a "shopping question". It is a "part identification" or "name that function" question from my POV. Tobia is not asking for a recommendation for a specific product, he is asking for the proper name or search term to use when he goes shopping. \$\endgroup\$ – Richard Crowley Jun 4 '16 at 19:58
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Yes. Look for dual-coil, latching relays. Available in a wide range of sizes and current capacity ratings.

enter image description here

Of course there are also solid state electronic equivalents as well.

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schematic

simulate this circuit – Schematic created using CircuitLab

Figure 1. Latching relay circuit.

This circuit may do what your require.

  • Pressing the ON button causes RLY1 to energise. The hold-on contact will keep the relay energised when the ON button is released. Pressing ON repeatedly will not affect the operation.
  • Pressing the OFF button will disconnect the relay which will then drop out. On release of the OFF button the relay will remain de-energised. Repeated pressing will have no effect.
  • On power up the circuit will default to off. (This is generally a good safety feature.)
  • OFF overrides ON. Again, this is generally a good thing.

Your relay will need at least two contacts. One for the hold-on and one for the load.

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    \$\begingroup\$ Yes, the circuit shown by JIm Dearden or transistor will latch as long as power is provided to the relay. There are also MECHANICAL latching relays which do NOT require continuous power to perform the latch function. \$\endgroup\$ – Richard Crowley Jun 4 '16 at 18:25
  • \$\begingroup\$ it might be possible to connect the load to the same contacts, if the on switch is strong enough to run the load and the load suits high-side switching. \$\endgroup\$ – Jasen Jun 5 '16 at 0:02

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