0
\$\begingroup\$

this might be super basic but for a geologist it is killing me. I need a low voltage AC device (specifically a dog training collar) to wire to a flashlight so when the remote is pressed the light turns on.

Would a relay (SPST) do this or a MOSFET or??

I have 2 wires off the terminals on the shock collar that output 2V AC at about 2000 uA.

The flashlight has a lead off the batteries to a manual switch. This component needs to replace that manual switch. I am pretty sure every action movie out there uses this scenario .. Lol

\$\endgroup\$
  • 2
    \$\begingroup\$ I expect some people here to get upset by the fact you are using the shock collar.. There were precedents. \$\endgroup\$ – Eugene Sh. Feb 28 '18 at 20:36
  • 1
    \$\begingroup\$ Provide a description of how you made the AC voltage and current measurements. What kind of tools? How were those tools applied? (This is a shock collar question and I think we need to be sure of things.) Also, what is the stated purpose of those two terminals that seem to be provided on this shock collar? \$\endgroup\$ – jonk Feb 28 '18 at 20:37
  • \$\begingroup\$ @EugeneSh. in his defence.. he did not say it was on a dog ;D \$\endgroup\$ – Trevor_G Feb 28 '18 at 20:39
  • \$\begingroup\$ Lol. The shock collar is not on a dog. I had one laying around and thought of it being a "free" remote control device. The multimeter indicates the voltage off of the 2 terminals on the shocking device. FWIW a 4KV cattle prod hurts worse 😂 \$\endgroup\$ – Brett H Feb 28 '18 at 20:52
1
\$\begingroup\$

You can take the AC and peak detect it to turn on a logic level MOSFET. Size R1 to adjust the turn on and turn off delay according to the frequency of the signal.

I'm concerned your AC voltage may be a lot higher than your meter is showing you though, so I added a 5.1V zener, D2, to protect the MOSFET.

HOWEVER : If the output you are measuring is the shock voltage, it will be in the killo-volts range so don't even think about hooking this up.

schematic

simulate this circuit – Schematic created using CircuitLab

\$\endgroup\$
  • \$\begingroup\$ Thanks Trevor! I am pretty sure it is just in the 2V range since it is coming off a 3V Li-ion battery and it doesn't appear to have capacitors in it. My cattle prod tests at 4KV when depressed. Fortunately my MM has a 4KV MAX ( I noticed AFTER I tested it😂) \$\endgroup\$ – Brett H Feb 28 '18 at 21:05
  • \$\begingroup\$ @BrettH these things usually are simple switched inductors though. The kickback voltage is what gives you the shock, and will be a short but large voltage. Basically the same thing as fires the spark plugs in your car. \$\endgroup\$ – Trevor_G Feb 28 '18 at 21:06
  • 1
    \$\begingroup\$ The kick WILL be in the kilovolt range as Trevor says ... probably too short for a multimeter, but unpleasant for dogs, fatal for MOSFETs. \$\endgroup\$ – Brian Drummond Feb 28 '18 at 21:16
  • \$\begingroup\$ Ahh thanks for the heads up. So in your proposal the 9V light is isolated from the shock collar current, right? \$\endgroup\$ – Brett H Feb 28 '18 at 21:16
  • \$\begingroup\$ @BrettH they need to share a common ground. If you want it isolated things get more complicated and you need a power source on both sides. \$\endgroup\$ – Trevor_G Feb 28 '18 at 21:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.