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Topic: track separation for mains voltages (Read 678 times) previous topic - next topic

dc42

The rest of the circuit looks OK to me. As the load is resistive, you could use a zero crossing opto triac such as MOC3042 instead of a random fire one, which would create less mains borne interference. But unless the heating element takes a lot of power, it's probably not necessary.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

pwillard

Yes, D3 is clearly redundant, since thats an optical diac in the coupler.

Is there any reason you opted to build your own versus use a Solid State Relay?

You can get a ready to use 10 AMP SSR from MPJA  http://www.mpja.com/, for example, for as little as $7.95.

dc42

SSRs cost a little more in the UK, however Farnell has a 1.2A one for £1.87 and a 2A one for £6.34, is that is enough for your heating element.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

mmcp42


The rest of the circuit looks OK to me. As the load is resistive, you could use a zero crossing opto triac such as MOC3042 instead of a random fire one, which would create less mains borne interference. But unless the heating element takes a lot of power, it's probably not necessary.


:) thanks
total power is only 1 kW (4.5 amps or so at 220 volts)
seems I'm actually using a MOC3080X - which is zero crossing :)


Yes, D3 is clearly redundant, since thats an optical diac in the coupler.

Is there any reason you opted to build your own versus use a Solid State Relay?

You can get a ready to use 10 AMP SSR from MPJA  http://www.mpja.com/, for example, for as little as $7.95.



parts cost < £1, SSR > £10
easy choice really - I'm a cheapskate by trade :)
no major reason other than it's part of a larger project
I'll have a look at what's available on this side of the puddle
there are only 10 types of people
them that understands binary
and them that doesn't

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