Power supply and conversion problem

Hi, I'm an arduino beginner and I'm trying to heat something with a quartz lamp that needs a 230V power supply. My problem is that I have a 12V 1 channel relay and I don't know if my relay can hold that kind of power or what should I use so I won't fry my equipments.

Which relay do you have? How much current does your lamp need?

A 12 volt relay might not be the best together with 5 volt logic. A transistor and some resistors will be needed. Use a 5 volt relay module if available.

1 Like

Can a 5 volt relay sustain a lamp supplied with 230V?

This is the relay that I have and the lamp need 230 volts, but now I realise that I don't think I can use the 12 volt relay directly on my board...

The relay is marked to indicate that it can manage 10A at that voltage, so as long as your lamp draws less than that it should be OK. Hopefully, it isn't drawing close to the limit.

As you have surmised though, you can't drive it directly from an Arduino.

1 Like

I have a few 12 volt relays. The trouble is that feeding it with 5 volt the relay does not have power to close the main contacts.
Feeding the relay with 12 volts will damage the 5 volt controller trying to switch the relay.

1 Like

Thank you for your help!
I'll see how it works with 5 volt relays

I, by mistake, bought some of those 12 volt relays and I have been working them through.....
As a general rule... Divide Chinese Amp ratings by 2. When they say 10 amp You are safe running 5 amp....

You can use the same module, but with a 5V relay.
5V Relay Module

1 Like

These cheap relays are.... cheap. I would not call them reliable. If whatever you are heating will be damaged if the lamp stays on for long periods of time then I would look for a more robust solution.

Perhaps an industrial quality SSR.

Thank you, but what I'm doing is more like a prototype and fortunately I don't need it to heat for long periods of time.
I appreciate the advise nonetheless :blush:

1 Like

This is the case when the thread author thanks for the help.
This does not happen every time. :slight_smile:

The trouble with relays is not so much how long you leave them on. It's how often you switch them on and off, and at what current. The contacts tend to burn in at higher currents, which happens mostly due to the sparks when switching on and off. Usually even a cheap relay will hold out for quite some time though.

1 Like

This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.