Looking for a sensor for measuring 220V AC

[e_eja]

i was looking for the sensor for measuring 220v line to lower voltage (some king like step down transformer) i try to use konvensional transformer that usually using for power supply but had some problem that when i look at oscilloscope the phase betwen input and output exhibit phase shif is there any solution?

help !!!!!!!

 

[bomba]

Re: measuring AC voltage

If you don't need insulation, you can use a resistor divider. You must to use over voltage protection array in order to prevent failure damage.

Best regards

 

[Aoxomox]

Re: measuring AC voltage

you could use a differential probe that allows direct, earth free measurement on power lines.
the question is in what you are interested.

Because you mention exessive phase shift you are probably interested in the zero crossing point of the mains voltage. This can be measured with a opto coupler.

If your transformer is very small (<5VA) then you have a lot of stray inductivity and thus results in a phase shift. May be you should put a load resistance on the secondary.

hope it helps

aOxOmOx

 

[Vicent Yang]

Re: measuring AC voltage

If you will connect the AC direct to you A/D input through a potential divider its best to implement your power supply direct from the AC line without a transformer. Because if you will use a transfer the circuit ground must be connected to the AC neutral and this will casue some problems to you. If you till us more about your application we can help you.

 

[ITP]

Re: measuring AC voltage

Hi,

You can use hall sensor (costly option) or opto isolator chips with linear CTR (current transfer ratio).
In both the cases you will get Isolation.

Regards
Itp

 

[Noman Yousaf]

Re: measuring AC voltage

hello
you can use mx536 IC
that is mV AC to DC converter
first decrease the voltage by using Resistor devider then make it DC by using such IC
then measure it

I hope it will help u

Noman

 

[Trishool]

Re: measuring AC voltage

It is simple use a capacitor in series to stepdown AC . You can make a potential divider and a transistor buffer there after simple isnt it . But dont forget to convert it to DC using Diodes Full bridge or half before measuring it.

Ts

 

[xvibe]

Why can't you use the transformer?
The phase shift will always be the same. If that's a problem.

 

[H_u_n_t_e_r]

measuring AC voltage

phase shift seems to be not important if you need just voltage measurement. But you need phase shift between current and voltage yes you right. You can overcome with microcontroller... subtract or add a treshhold value and compansate it.
rgrds

 

[aym_qunibi]

Re: measuring AC voltage

you can do it byusing multiple drop resistor in series (protection against worst case any resistor damage will be open and decreases size) then by using a halfwave rectifier feed it to the ADC in your µc.