Hello,,,
i am using in one application TRIAC relay non cross 2 A from sharp.
unfortunately i have not found this type of relay, and i want to use another relay but this relay is MOSFET relay.
theses two relay are exactly the same but one TRIAC and the other MOSFET.
is it possible to use MOSFET as an alternative?
with MOSFET relay there is also zero cross and non zero cross ?
many thanks in advance
If they are "exactly the same", what's the issue?
Do you have links to the datasheets?
with MOSFET relay there is also zero cross and non zero cross ?
I don't know but zero-crossing is a "feature" so non-zero-crossing should be the default.
thanks for replay
it is just to get more information if the MOSFET relay could be an alternative for TRIAC relay
my TRIAC relay is non zero cross but it is not written in the datasheet of MOSFET relay if it is non zero cross.
MOSFET relay : http://www.relay.com.tw/upload/2017/06/14/1497428572.pdf
TRIAC relay : http://www.mouser.com/ds/2/365/s102t01_e-310942.pdf
It appears these MOSFET SSRs have relatively low curent ratings.
Nevertheless, if you are using them within the specifications - and provide adequate drive to the LED, they should work just fine.
Why do I mention "adequate drive"? Because if you do not provide sufficient drive, they will not turn on fully and will overheat. A TRIAC either switches on or does not - it cannot be partially switched on whereas the MOSFETs can. This has nothing to do with "zero crossing" switching - that is an extra piece of circuitry.
Paul__B:
It appears these MOSFET SSRs have relatively low curent ratings.Nevertheless, if you are using them within the specifications - and provide adequate drive to the LED, they should work just fine.
Why do I mention "adequate drive"? Because if you do not provide sufficient drive, they will not turn on fully and will overheat. A TRIAC either switches on or does not - it cannot be partially switched on whereas the MOSFETs can. This has nothing to do with "zero crossing" switching - that is an extra piece of circuitry.
isn't a property of triac that it turns-off on zero-crossing (only)?
as i know with MOSFET relay, there is no zero crossing. this is just for TRIAC relay
i am asking to make sure before order the MOSFET relay.
acharbeck:
as i know with MOSFET relay, there is no zero crossing. this is just for TRIAC relay
i am asking to make sure before order the MOSFET relay.
there are two aspects of zero crossing if you use a triac for phase cutting. pulse the triac some time after zero crossing and then the triac self turns off AC on next zero crossing. to know when to pulse the triac, you need an additional zero crossing detector circuit.
if you want to use the component as a relay then a triac which is made to work as a relay and not turn off the line on zero crossing works the same way as a MOSFET
Juraj:
isn't a property of triac that it turns-off on zero-crossing (only)?
Oh dear!
In normal operation, a Triac will only turn off when the current falls to near zero (the actual cutoff or "hold" current is part of the specification). If the load is resistive, that will correspond to the zero crossing of the supply voltage.
A "zero crossing" TRIAC (or actually, opto-coupler) refers instead to one with a circuit which shunts the gate and prevents triggering when there is any significant (few volts) voltage across the main terminals so it will only switch on as the AC wave passes through zero. This has the advantages of minimising switching transients and in particular, the charging current of a capacitor across the load.
With the MOSFET SSR, it can switch either on or off at any desired part of the cycle and can be used for "trailing edge" phase control dimming.
Paul__B:
Oh dear!In normal operation, a Triac will only turn off when the current falls to near zero (the actual cutoff or "hold" current is part of the specification). If the load is resistive, that will correspond to the zero crossing of the supply voltage.
A "zero crossing" TRIAC (or actually, opto-coupler) refers instead to one with a circuit which shunts the gate and prevents triggering when there is any significant (few volts) voltage across the main terminals so it will only switch on as the AC wave passes through zero. This has the advantages of minimising switching transients and in particular, the charging current of a capacitor across the load.
With the MOSFET SSR, it can switch either on or off at any desired part of the cycle and can be used for "trailing edge" phase control dimming.
and now what is a "Non-Zero Cross type" of Triac referred by OP. it will turn-off and stay off while the current is near zero?
Juraj:
and now what is a "Non-Zero Cross type" of Triac referred by OP. it will turn-off and stay off while the current is near zero?
It is a TRIAC.
I sure wish the OP would clairify what he’s switching, AC or DC, the type of load and it’s current requirement. Otherwise, we’re just just playing x-y problem
acharbeck:
TRIAC relay : http://www.mouser.com/ds/2/365/s102t01_e-310942.pdf
from the datasheet
S102T01 Series
S202T01 Series
Features IT(rms)≤2A, Non-Zero Cross type
Low profile SIP 4pin
Triac output SSR1.
Output current, IT(rms)≤2.0A2.
Non-zero crossing functionary
this is what OP uses now. @WattsThat, I doubt it would work with DC
TRIACs are for switching AC. They need a short pulse at the gate to switch on, and switch themselves off when the current drops to zero, and can be used to regulate current by phase cutting (most AC SSRs do not support this, but may have a circuit to switch on at the zero crossing). A TRIAC is unsuitable for DC as in this situation it can not switch off.
MOSFETs are for switching DC. They switch on when there's a voltage on the gate relative to the source, off when the voltage on the gate is equal to that of the source. They can regulate current by PWM modulation. A MOSFET is unsuitable for AC as it can block current in only one direction (the body diode will conduct the negative phase - until it burns out).
Long story short: no, you can't just replace a TRIAC based SSR with a MOSFET based one.
wvmarle:
TRIACs are for switching AC. They need a short pulse at the gate to switch on, and switch themselves off when the current drops to zero, and can be used to regulate current by phase cutting (most AC SSRs do not support this, but may have a circuit to switch on at the zero crossing). A TRIAC is unsuitable for DC as in this situation it can not switch off.MOSFETs are for switching DC. They switch on when there's a voltage on the gate relative to the source, off when the voltage on the gate is equal to that of the source. They can regulate current by PWM modulation. A MOSFET is unsuitable for AC as it can block current in only one direction (the body diode will conduct the negative phase - until it burns out).
Long story short: no, you can't just replace a TRIAC based SSR with a MOSFET based one.
right. I saw somewhere, someone used two MOSFETs instead of a triac
That may work as well. Still I'd prefer a TRIAC as the reverse voltage a MOSFET can handle is typically not that high.
wvmarle:
Long story short: no, you can't just replace a TRIAC based SSR with a MOSFET based one.
Then you have failed to do your research on the device cited in reply #2.