0
\$\begingroup\$

I have the project of making a touch switch using the IRFZ44N MOSFET for making a small led glow and stop glowing when I touch the probes. I thought of using a relay if I have to make a bulb glow, by connecting to the plug directly. I searched on the internet and found that most projects used 5V relays. But is it a problem if I use a 12V relay, instead of a 5V relay?

(Please don't mind if the question sounds silly, I am new to electronics and electrical)

\$\endgroup\$
2
  • 2
    \$\begingroup\$ There's a schematic button on the editor toolbar. Draw a schematic of your idea. Double-click to edit component properties. You need 12 V to energise a 12 V relay. Edit your question to explain if you have 12 V or not. \$\endgroup\$
    – Transistor
    Mar 24, 2020 at 17:45
  • \$\begingroup\$ Probably, provided the supply voltage is 12V, perhaps with minor changes. Show us your proposed schematic. \$\endgroup\$ Mar 24, 2020 at 22:56

2 Answers 2

2
\$\begingroup\$

No. You cannot. You can, however, use a 5V relay instead of a 12V relay as long as you put the appropriate resistor in series with the relay coil (so that the relay coil sees the same voltage across it and thus current through it that it normally needs).

What you are going to need to do (other than getting a 5V relay) is to re-design your circuit to accommodate the 12V relay which, depending on the circuit could be very simple or could be involved. You basically replace the 5V supply with a 12V supply and this causes a cascade of changes for everything that relies on the 5V supply in one way or another.

\$\endgroup\$
1
  • \$\begingroup\$ But the serie resistor should be able to handle quite enough power dissipation. And think about consumption when you have several relays working continuousely. Better have a power supply which matches the relay voltage. \$\endgroup\$
    – Fredled
    Mar 24, 2020 at 22:04
0
\$\begingroup\$

No. you can't.Because you need a threshold voltage close to relay voltage to triggering it. Thanks.

\$\endgroup\$
1
  • \$\begingroup\$ This does provide a correct answer, although I would pick other terms: Because you need a "must operate voltage" [which is] close to [the] relay "nominal" voltage to trigger it. \$\endgroup\$
    – Huisman
    Mar 25, 2020 at 18:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

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