What do you use to measure your flyback output ?

[khelz]

Wassup guys,

got a question for ya ! What do you guys use to measure your flyback output voltage ? Also, do you got any ideas with how can I get a visual of the output waveform ?

-Khelz-

 

[cowana]

When you say a visual output, do you mean a voltage/time graph?

If so, make a pickup coil of a few loops of wire, attach it to the scope probe, and put the pickup coil near the flyback (but not so close it arcs). That should give you a rough picture of the waveform.

 

[khelz]

Okay. But how can I get the idea of the output voltage then since we dont know the turns ratio of the flybacks ?

 

[crutschow]

Is the voltage high enough to generate an arc? If so you can make a rough estimate by high far the arc will jump.

If it's a lower voltage, then you could generate a high voltage probe with series resistors. Nine 10MΩ resistors in series will give a 10:1 attenuation into a multi-meter with a 10MΩ input impedance. Solder the resisters in a string and cover with shrink tubing.

 

[khelz]

But do the resistors will change the waveforms of the voltage ? Because what I want to know is how much the waveform is similar to a perfect square wave. So if the resistors change it a lot, my analysis become useless...

 

[bychon]

Any time you measure something, that something is changed. One way to compensate is compare the impedance of your flyback transformer to 100 million ohms and calculate how much the wave shape will change. If the results of your calculation are not acceptable, you will need to get more than a hundred million ohms and try to measure the voltage with that.

Mouser Electronics - Electronic Component Distributor has some excellent 1% resistors as high as 1000 million ohms each.

 

[khelz]

Because the more impedance my resistors got, the less they will affect the curve because they will allow less current to pass ?

 

[bychon]

You guessed it! **broken link removed**

 

[Ubergeek63]

Wassup guys,

got a question for ya ! What do you guys use to measure your flyback output voltage ? Also, do you got any ideas with how can I get a visual of the output waveform ?

-Khelz-

it is also possible to measure the reflected voltage.

the drain waveform starts with the switch saturation voltage when the switch is on.

when the switch is turned off there is a huge spike, that the snubber is for (to protect the switch), caused by the leakage inductance

and then the plateau that is the reflected voltage that is ideally the output voltage times the turns ratio for the duration of the time that the current is actually being supplied to the load.

dan

 

[khelz]

thx guys !