"Jon Mcleod" wrote in message
m...
A few weeks ago, I asked about generating an 140kHz electric field
across a leaf, part of a bio-med lab. Thanks for the answers. But it
turns out I misread the roster and was in the wrong group.

What I ACTUALLY NEED to do is generate a 100kHz electric field, at
1v/cm, across a T-Bone steak, to measure whether it retards or
accelerates decomposition over time. The hypothesis is that the
e-field retards growth of certain bacteria inside the meat.


Hi Jon

At your frequencies, a slab of meat will mostly resemble a resistor with
some capacitive reactance. The resistance will vary with the thickness
and area of the slab you're applying the signal to.

Memory fades, but I recall that you will be looking at resisitivities on
the order of a few hundred ohm-cm. (R = rho * L / A).

At a field strength of 1 V/cm, the power levels will be pretty low --
the meat won't cook noticeably. The currents should be manageable, that
is, I believe that your signal generator will be able to hold the 1V/cm
without additional amplification.

This will be true as long as the load resistance is the 50ohm output
impedance of the signal generator. There is a decent chance that your
meat slab will be less than the desired impedance. In this case you
will need to measure the voltage periodically and adjust the generator
output: As the meat degrades, its conductivity should be increased by
the spillage of conductive cell contents.

You will want to apply the field directly to conductive plates which are
in contact with the meat -- if you have any air gap between a plate and
the meat,
the voltage drop will essentially be all across the air gap, none across
the test sample.

Best regards
PN2222A

NPN (Is = 14.34f Xti = 3 Eg = 1.11 Vaf = 74.03 Bf = 255.9 Ne = 1.307 Ise
= 14.34 Ikf = .2847 Xtb = 1.5 Br = 6.092 Isc = 0

Ikr = 0 Rc = 1 Cjc = 7.306p Mjc = .3416 Vjc = .75 Fc = .5 Cje = 22.01p
Mje = .377 Vje = .75 Tr = 46.91n Tf = 411.1p Itf = .6

Vtf = 1.7 Xtf = 3 Rb = 10)