Firstly, apologies as I'm very new to electronics!

I'm converting an old broken Atari 2600 to be an enclosure for my ODroid UX4 single board computer. I thought it would be nice to be able to run the odroid's power wire (5.0V/4A DC) through the Atari's original power switch (https://console5.com/store/atari-2600-slide-switch-power-difficulty-color-new-old-stock-c010373.html) so it actually works as a power switch but not sure if this would be safe- if the switch would handle that kind of power? Can't find any details about the switch or what it is rated for? Is there anyway to test this or are the voltages/ amps so low that it's not a concern?


1 Answer 1


You can test a switch for the maximum current it can handle, but then you'd have to get a new one to actually use.

Look carefully at the switch. Often such values are stamped right on it, especially for large toggle switches. If you can find the model number, then you can look up what the rating is.

Otherwise, you can get a start by measuring the current it switches in its intended operation. If the circuit was designed properly, that should be at least a bit less than the full rating.

If you don't know and don't want to take a chance overloading the switch, then you can have it turn on a relay, then have that relay do the actual switching. Relays to switch 4 A should only take a few 10s of mA at 5 V.

Or, you can replace the existing switch entirely with a part you of known specs.

  • \$\begingroup\$ Brilliant, thank you. These switches are probably almost as old as me, the original console I have was built in the early 80's so no luck finding any specs and the switches only have a single marking (an M in a circle) which I assume is the manufacturer? I think the safest bet sounds like a relay, I'll get googling! Thank you for your advice. \$\endgroup\$
    – Shawson
    Sep 3, 2018 at 10:13
  • \$\begingroup\$ I've created a demo on tinkercad- am I correct in thinking that the switch here will only get milliamps load while the computer (or motor here) will get the full 4 amps? tinkercad.com/things/dI3Cybibsxc-relays-demo-lu-5-r/… \$\endgroup\$
    – Shawson
    Sep 5, 2018 at 19:31
  • \$\begingroup\$ I don't know from "tinkercad", but the switch only needs to support the extra current to activate a relay. The relay then carries the 4 A additional full power current. \$\endgroup\$ Sep 5, 2018 at 19:37
  • \$\begingroup\$ Am I correct in thinking this doesn't require two power sources? As the relay coil needs power to be triggered, but can I run everything off of one power source? Lots of circuits I've seen seem to use a separate battery for the coil side of the relay? \$\endgroup\$
    – Shawson
    Sep 5, 2018 at 22:47
  • 1
    \$\begingroup\$ @Sha: Since everything will have a common ground, you can use a single power source if it can supply the total power. \$\endgroup\$ Sep 5, 2018 at 22:57

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