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Topic: rectified AC phase control (Read 8594 times) previous topic - next topic

TomGeorge

Hi,
Where are you probe gnds connected?

Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

dgueorguiev

Hi Tom, for the Arduino circuit both probe GND are connected at the point were ARDUINO GND is connected to the schematic. for the high voltage both probe GND are connected were "-" from the rectifier bridge is connected to the schematic .(I show on last posted schematic),but may be is not readable .

TomGeorge

Hi, 
Okay ,I understand what connections you have.

Now in the high voltage trace you have gnd of both probes connected to the -ve output of the rectifier.
You have Ch2 probe connected to pin4 of the lower 4N35, U2?.
Your circuit shows Pin4 connected directly to -ve output of the rectifier, so how are you able to measure a 68V signal.
You should have a flat trace at probe gnd reference.

PLEASE double check your wiring, TURN the power off and use your DMM to measure the resistance between -ve rectifier terminal and pin4 of the 4N35.

Can you use the full screen of the scope please for the two channels.
I don't see a need for a 100nS sweeping display when we are looking at 60Hz signals. so just get rid of it.


Thanks.. Tom... :o :o
Everything runs on smoke, let the smoke out, it stops running....

dgueorguiev

Resistance is 0.6 Ohm. looks like I have damaged GRN of my scope , that is why I have all this weird pictures that have no sense .

one more attempt.  I install parallel to U1(4N35)  optocoupler MOC3041 and connect pin 6 with same signal that is going to pin5 of U1 ,and you can see now what i have on channel 2 of my scope monitoring pin4 of this MOC3041.

dgueorguiev

I am sorry I forgot to connect pin4 of MOC3041 to "-" of rectifier bridge in previous post. now the picture of signal is the same

dgueorguiev

Looks  like my scope adding half wave with minus value to the 0 V value of "-" point of the rectifier bridge. There no other explanation .

TomGeorge

Looks  like my scope adding half wave with minus value to the 0 V value of "-" point of the rectifier bridge. There no other explanation .
I would say you have damaged your scope, probably because you do not understand about gnd and mains supply.
Until you get the problem fixed, all you scope displays will be invalid.
Just the fact that you connect gnd of the probes to a DC rectifier that is DIRECTLY connected to the mains supply is where you scope will have been damaged.
DO NOT CONNECT gnds to ANY LIVE directly connected circuit.
Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

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