hello,
I am trying to control 100 W bulb using relay that is to be controlled through arduino uno. The relay i am using is attached (Double channel relay). I am using a separate 5V dc to JDVcc of relay (I removed jumper wire between JDVcc and Vcc of relay). I want to know if i can do it safely or not. Thank you.

 

hi,
You will only get the mains isolation between the 5V and the Logic inputs, that the output relay contacts provide.
The 0V line is always connected between the logic side and the emitter of the relay drive transistor.
On my version of that PCB module, the logic inputs are pulled Low to operate the Relays.
E

 

hi,
You will only get the mains isolation between the 5V and the Logic inputs, that the output relay contacts provide.
The 0V line is always connected between the logic side and the emitter of the relay drive transistor.
On my version of that PCB module, the logic inputs are pulled Low to operate the Relays.
E

Will the bulb light up if i give "LOW" signal to the pin 7 of arduino?

 

hi,
If the JD Link is in position the relay coil will draw power from VCC, if not linked, you need to supply 5V to the JD_VCC.
Pulling INA low will energise the relay.
The circuit for one input is attached.

NOTE: The opto coupler provides NO isolation as the OV line copper is common to the transistor and the 0V input.
E

 

They do mention sink to common to activate relay.
Max.

 

hi,
If the JD Link is in position the relay coil will draw power from VCC, if not linked, you need to supply 5V to the JD_VCC.
Pulling INA low will energise the relay.
The circuit for one input is attached.

NOTE: The opto coupler provides NO isolation as the OV line copper is common to the transistor and the 0V input.
E

Thank you so much and If i want to control a 1000 watt heating element in a similar manner as above, what additional changes should i make and which relay will be best for doing so?

 

At what voltage?
You could use an off the shelf SSR, this offers isolation also.
Max.

 

At what voltage?
You could use an off the shelf SSR, this offers isolation also.
Max.

My voltage is 220 V. Can you suggest me a circuit diagram for its use to control heating element through arduino?

 

The relays you show are purported to be 10amps, so they may work for you.
The alternative is to use a MOC3162 opto and a Triac.
Max.

To implement higher current relay version.




A 2n7000 fet could be used in place of bi-polar transistor.

 

The relays you show are purported to be 10amps, so they may work for you.

for 1000 watt also(with the relay i have attached in question)? I think there are inbuilt optoisolator and transistor with it as shown below. means i can connect them directly as i have connected a bulb (in my first picture of question)?

 

hi r,
I would say that is OK, as per your first post.
Be aware a Tungsten lamp can draw upto 5 times its running current for a few 10s of millisecs when powered up from cold.
E

 

hi r,
I would say that is OK, as per your first post.
Be aware a Tungsten lamp can draw upto 5 times its running current for a few 10s of millisecs when powered up from cold.
E

thanks and for 1KW resistive heating element?

 

hi,
The current will be higher than 1000W/230Vac for a few seconds while the element heats up.
E

 

@rameshadkri You have about a 2.2Kw leeway at switch on with a 10amp relay.
Max.