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Adam850

Triac help

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I am trying to use a triac to replace a broken relay in a circuit I made. A 555 is setup to flash on and off about every second. The positive pulses go to a relay, which controls a 60W 120VAC light bulb. I have bought a triac to replace the relay, but I don't exactly know how to use it.
Relay:
Coil: SPST 12 volt, 20mA, 250 ohm
Contacts 0.5A @ 125 VAC
Triac:
VRRM: 300V
ITRMS: 4A Max
IGT(I & III) 30 mA Max
VGT 2.5 V Max
IH 30 mA Min

How can I use this triac?
P.S.
Do I need to heat sink it?

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Adam,

Not so fast! If you look at the datasheet you see that you need a few more parts to make it work. First a series resistor for the input (or you blow the led inside). And also a snubber circuit to help the triac get the correct gate current and such you can see an example of this on page 4.

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Adam,

The filament is not very inductive, consider it as an resistive load. You can omit the extra gate at pin 2 just connect pin 2 to neg on your timer circuit. The capacitor should be rated 250VAC. I understand why your relay is broken, a one second on off time will kill any relay quite fast. This new circuit will not be worn out.

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Adam,

The Rin resistor is the series resistor for the LED inside the opto. If you have 12 Volts input (vcc) a 390ohm 0.25W resistor will work. For the rest of the resistors use 0.5W or higher.

Always be careful with mains, don

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