What is the smallest physically-possible voltage that can be detected or processed given the state of today's technology?

Hi:

What is the smallest physically-possible voltage that can be detected
or processed given the state of today's technology?


Thanks

On Mon, 1 Jun 2009 17:15:19 -0700 (PDT), GreenXenon


You can buy nanovoltmeters that will resolve a couple of hundred
picovolts, if you're careful.

Superconductive SQUID detectors can measure a picovolt.

Single-electron transistors can sense, well, single electrons.

John




On Mon, 01 Jun 2009 17:40:20 -0700, John Larkin


PMTs can be good enough to detect single photon events.

On Jun 1, 10:33=A0pm, ItsASecretDummy

Hmmm... I have a $35 digital multimeter that can measure exactly 0
volts!

Rick


rickman wrote:


No, it can't. It can display zero, even with some voltage at the
input. The issues is the resolution of the meter. Even with the probes
shorted, you will have some Johnson noise which is generated by the
resistors in the input circuitry, if the meter is above absolute zero
degrees. That voltage is too low to be displayed, but it is still there.


--
You can't have a sense of humor, if you have no sense!