ESL voltages

[Fanuc]

Hello a quick one on electrostatics,

If the diaghram is set at - 2 KV, does that mean the stators can go up to 1KV on both sides. Not at the same time obviously.

Or does it mean one of the stators can go up to +2KV ?

Thanks for any help

 

[MarkRehorst]

Voltage measurements are always relative. The diaphragm voltage is usually measured relative to the stators. So if the diaphragm is at -2000V relative to the stators, then both stators are considered to be at 0 V. Conversely, you can measure the voltage of the stators relative to the diaphragm, in which case the reading will be +2000V (while the diaphragm is considered to be at 0 volts by definition). You can also measure the voltage of both the stators and the diaphragm relative to some other reference point, in which case you may measure the diaphragm to be at +3000V and the stators to be at +5000V. The difference between the voltages will always be 2000V, with the stators more positive than the diaphragm, assuming the negative terminal of the bias supply is connected to the diaphragm.

I forget who's law it is, but there is one that states that potential is the same everywhere along a conductor. Both stators are connected by wire to the center tap of the transformer which is in turn connected to the bias supply. Its all one big conductor, therefore the voltage is the same everywhere- i.e. both stators are at the same potential.

I_F

 

[Fanuc]

Hello,

Thanks for the reply. I think I follow you regarding the measurements relative to ground etc. Need just alittle more help.

If the diaghram is at -2KV dc and stators are at 0V say. Can one of the stators (hence AC musical signal) go up to +2Kv at full excursion. Hope my question makes sense! 🙂

Thanks

 

[Calvin]

Volta

Hi,

usually the voltages measured are referenced to the mid-point of the Audio-tranny. This point is often referenced to ground potential (0V).
Depending on the polarisation of the power supply the diaphragm measures positive or negative DC-potential. The stators would measure 0V because there is no DC voltage-drop over the audio tranny. If You take the diaphragm as reference point (0V) than the mid-point of the tranny -and so the stators as well- would have aquire the DC-potential of the power supply. Most esls are referenced to a DC stator voltage of 0V because of safety reasons.
If e.g. the potential is 2000V the maximum undistorted signal can reach 2000V peak, that is 4000V peak-peak, that is ~1400V rms.
Raising the signal above the peak value will result in high distortion because then the esl functions as a rectifier with twice the signal frequency.

jauu
Calvin

 

[Bazukaz]

One question : is it theoretically possible to charge each side of diapraghm with different potencials , and drive stators in-phase ?
Then the driving system should not see capacitance ?
Is my thinking totally wrong ?

 

[MarkRehorst]

How would you apply the drive signal to this?

I_F