Need 2m - 240V Ohm resistor - where to find ?

[skippybangkok]

Have an old home automation which will die one day soon, and stumbled one Tuya which is 1. Cheap 2. works good

 

Using a wifi wall switch with only L, L1,L2,L2 , but no N ( they have same with N terminal too ).

 

it needs a leak current to enable the switch and wifi, and they use a capacitor, but the capacitor needs to be placed over L, and then behind the load on L1 which is impossible as N does not come back to where the switch is.

 

Would like to make a dummy load, and add ie 2M Ohm 240 volt resistor to simulate the LED light, which I can solder into the switch socket.

 

Not sure where to buy, as never have bought this in my 27 years in thailand

 

Thanks 

[CharlieH]

MOVED TO ELECTRICAL forum

[Crossy]

2M at 240V is about 120uA so any 1/4W resistor would do the trick.

 

Since this is intended to work on the mains I suggest using 4 x 220k resistors in series, most resistors are intended to work at these voltages, but one can never be too careful.

 

Lazada is your friend here, if you need 100!

 

I would visit your local TV fixing man and ask if he has. They are tiny money!

 

But there's no reason why you couldn't use a capacitor in the same place is the resistor. Make sure it's a mains rated one.

 

You might want to post a sketch of what you intend doing so we can tell if it will actually work!

 

[OneMoreFarang]

http://www.es.co.th/detail.asp?Prod=015023668

 

10 for 4.5 THB

 

If you want to buy them in a shop they have hundreds of shops like that in Ban Mo 

Edited April 25, 2022 by OneMoreFarang

[skippybangkok]

Thanks for your help. My electronics is about 30 years out of date. 
 

As per image below, vendor says to put capacitor they provided after the load over L and L1. 
 

But N does not come back to the switch so can’t do that. So my thought is to simulate a load like the light at the switch - the light i measures is 2M ohm resistance 

 

 

[skippybangkok]

[SomchaiDIY]

1 hour ago, skippybangkok said:

This diagram  of capacitance at lamp L1 can make some sense 

 

Is possible L1 has internal option circuit to supply electronics using some capacitor at first lamp

 

This idea can be used when no neutral at switch

 

When ac wave is low lamp capacitor can make discharge on L1 line to power electronic circuit through neutral

 

 

[skippybangkok]

5 hours ago, SomchaiDIY said:

This diagram  of capacitance at lamp L1 can make some sense 

 

Is possible L1 has internal option circuit to supply electronics using some capacitor at first lamp

 

This idea can be used when no neutral at switch

 

When ac wave is low lamp capacitor can make discharge on L1 line to power electronic circuit through neutral

 

 

Yes....  one option would be to go to the light itself and put the capacitor over that.  It does work, tested it. but prefer to leave the light fitting alone and handle the seepage at the switch side if possible

 

[Crossy]

Is there an outlet nearby where you could pick up a neutral??

 

Is the switch box grounded (it should be). You could use the ground instead of the neutral in the L1 design . The leakage is small so it shouldn't affect your RCD/RCBO (it's really no different to having a mains filter).

 

What value is the capacitor??

 

Note that this really isn't recommended particularly when there's an easy solution at the light itself.

[skippybangkok]

On 4/27/2022 at 7:31 AM, Crossy said:

Is there an outlet nearby where you could pick up a neutral??

 

Is the switch box grounded (it should be). You could use the ground instead of the neutral in the L1 design . The leakage is small so it shouldn't affect your RCD/RCBO (it's really no different to having a mains filter).

 

What value is the capacitor??

 

Note that this really isn't recommended particularly when there's an easy solution at the light itself.

Thanks. Agree, but there is not a ground in the light switch box. might be lucky to find them in wall sockets.

 

Your right - the leak is very small, just has be enough to power the wifi in the switch.

 

have 10x  ( min order ) resistors arriving today - will see how it pans out. 

 

Thanks 

[skippybangkok]

capacitor 4.5 uF

 

[Crossy]

9 minutes ago, skippybangkok said:

capacitor 4.5 uF

 

About 700k ohms at 50Hz, so 300uA leakage.

[skippybangkok]

Thanks

 

[carlyai]

18 hours ago, Crossy said:

 

About 700k ohms at 50Hz, so 300uA leakage.

Is that 700 ohms or 700 k ohms?  Xc=1/(6,28×50×4.5/10^_6). I could be wrong. ????

[Crossy]

11 minutes ago, carlyai said:

Is that 700 ohms or 700 k ohms?  Xc=1/(6,28×50×4.5/10^_6). I could be wrong. ????

 

No, you are not wrong. Sadly there's no prize for spotting my deliberate error, only a factor of 10^3 adrift ???? 

 

I thought it looked wrong but other things came along as they do ...

 

So the leakage is up to 300mA!  

[carlyai]

57 minutes ago, Crossy said:

 

No, you are not wrong. Sadly there's no prize for spotting my deliberate error, only a factor of 10^3 adrift ???? 

 

I thought it looked wrong but other things came along as they do ...

 

So the leakage is up to 300mA!  

In the last 30 years, that's twice you've been wrong. Now me, I'm usually wrong more than right.  ????