Hello all,

I want to create high frequency AC electric fields for a biochemistry project. The frequency is to be kept variable from 10 kHz to 10 MHz (I can accommodate some change in this). So, my plan is to use printed electrodes and apply an AC signal to them. The voltage provided to the electrodes is also to be variable and the maximum should be at least 50 V peak-to-peak. I will use a function generator to obtain the initial signal and then plan to use an amplifier. How should I go about designing such an amplifier? I have as good as zero experience in amplifier design. Please help.
If there is a ready-made product available which fits my requirement, I can consider that too; but, our budget is not very high.
Thanks in advance.

 

You have yet to specify the output current required.

Google high voltage opamp and look at numerous offerings from various manufacturers, particularly:

Linear Technology
Maxim
Texas Instruments

50V peak-to-peak is not a problem, i.e. ±25V is not uncommon.
10MHz bandwidth is the more limiting specification.

 

I think the current requirement is minuscule, the signal is to be applied to closely spaced electrodes kept under a plastic coversheet. So, I guess to the order of nanoamperes?
I will look for the ICs, thanks.

 

At 10 Mhz the current could be significant due to the capacity between the plates. You will have to calculate the capacitance between the electrodes (From their area and the spacing between them. If they are not separated by air then you will also have to take into account the dielectric constant of the material between the electrodes.) From the capacitance you can then calculate the reactance at 10 Mhz so you can work out the current required to produce the required voltage between the electrodes. At 10Khz the current required will only be one thousandth of that required at 10 Mhz.

Les.

 

I am using printed electrodes, file attached. The capacitance would be minimal then, right?
I also checked the manufacturers for a high voltage high frequency op-amp, but MrChips is right, I did not find any with both, voltage and frequency range. So I think I have to make one myself. Can you please suggest some guides/tutorials which will help me?