I'm looking at this Form C relay: IXYS LCC110

Its max load current is 120 mA and max voltage is 350 VDC. My question may be dumb, but can I use this relay to safely control a load that is only 5V but 700 mA?

  • \$\begingroup\$ Since 700mA > 120mA : No. \$\endgroup\$
    – brhans
    Sep 8, 2017 at 0:41
  • \$\begingroup\$ if switching DC, why not use a mosfet instead of an ssr? \$\endgroup\$
    – dandavis
    Sep 8, 2017 at 13:07
  • \$\begingroup\$ I need something that can change a circuit's path, as in a SPDT relay, and not really an on/off switch. Is this something simple I can do with MOSFETs? \$\endgroup\$ Sep 9, 2017 at 5:47

1 Answer 1


Unfortunately, no. You can't exceed any of the ratings, even if the other one is far from the limit. These ratings exist for different reasons and the device will fail in different ways, but it will fail if you exceed the absolute maximum ratings. Look a bit further and you will find a device that suit your needs for higher current and lower voltage.

  • \$\begingroup\$ Unfortunately I can't find a SPDT small solid state relay that can handle something around 5V and ~700mA. \$\endgroup\$ Sep 9, 2017 at 5:51
  • \$\begingroup\$ Try taking a look at some of the options in the link in my next comment. As a rule of thumb, you should choose something that is at least 20% above the ratings you are planning on driving it. So if you want to have 5 V on the output, I recommend you get a relay or MOSFET that can handle at least 8 - 10 V. Similarly, choose a value for the current that is a little above what you intend to put through it. \$\endgroup\$
    – Lucas
    Sep 9, 2017 at 13:57
  • \$\begingroup\$ digikey.com/products/en/relays/solid-state-relays/… \$\endgroup\$
    – Lucas
    Sep 9, 2017 at 13:59
  • \$\begingroup\$ Thanks Lucas, the problem though is that of those are all SPST relays. I need something that is a Form C (i.e. SPDT) that can control the flow of current. I don't want the current turned "on or off," but rather directed to one component or to another \$\endgroup\$ Sep 9, 2017 at 14:52
  • \$\begingroup\$ Oh, that's right, sorry. Well, in that case, is a mechanical relay an option? Do you really need insulation between the control signal and the load? If you need insulation, probably the best way is to bite the bullet and go for a mechanical relay. If you don't need isolation, you can accomplish this with a fairly simple combination of transistors. \$\endgroup\$
    – Lucas
    Sep 9, 2017 at 15:30

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