Re: EDN: Measuring Nanoamperes

Mike Monett <No@xxxxxxxxx> wrote:

> Here's a copy of a post I made earlier with info on RFSet,
> including the waveforms on a 5.5 electron triangle wave. (They
> don't show how a triangle wave can be made using 5.5 electrons:)

Actually, looking at Fig. 3A again shows each electron arriving at
the gate. Here's the text:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The rapid response of the RF-SET in the time domain can be seen by
examining the amplified output of the rectifying diode on a
digitizing oscilloscope. The average of 2048 individual traces,
taken with a large amplitude (Dqg 5 CgVg ' 5.5 e peak-to-peak)
10-kHz triangle-wave signal applied to the gate, is shown (Fig. 3A).

The output indeed follows the sinusoidal transfer function, passing
through five successive maxima (one for each electron added to the
island), and then reversing at the turning points of the gate signal
(dotted line). The S/N ratio is also quite high.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Averaging 2048 waveforms improves the SNR by

20 * log(sqrt(2048)) = 33.1dB,

so an individual electron may not be visible in a single sample.

Regards,

Mike Monett
.

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