A very silly oscillator

Ok, so where do you find 22Gohm resistors, other than in glass tubes and at the input to electrometers :-)...

Regards,

Chris

IMS, in 0805. I have samples of their 100G and 1T parts.

John

I bought some 1 G and 10 G ohmite ones from Newark. search under high voltage resisitors.

George h.

Not as rare as you'd think--used widely in trans-impedance amps.

The really nice thing about SPICE is the way it keeps your parts nice and clean--no nasty leakage that way to gum up the works.

-- Cheers, James Arthur

Then the guy standing next to the unit light up a pipe. One puff and ...

In the Bay Area when the fog rolls in the same thing would probably happen. Unless you pot this whole thing up.

Looks to me like a wet dream could kill it ;-) ...Jim Thompson

Not sure if they do a full E12 range up there. But 100G is available.

In mass spectrometers as the Faraday cup amplifier current to voltage conversion - although it was traditional to use 10^11 ohm resistors.

Batch to batch variation was amusing especially when the guy who made them for decades retired in the early 90's. They needed feedforward compensation on the amplifiers to tune out the misbehaviour(s).

Regards, Martin Brown

Won't even simple stuff like humidity screw them up? Not to mention EMI

Yeah, but that's a lonnggg shot... :-)

-- Cheers, James Arthur

That's a feature--humidity sensing, and--you'll like this Joerg-- cheap!

I strongly suspect in real life the device leakage currents would be too high for it to go. That's why it's a very silly oscillator. But, who knows? I haven't measured, not real parts, not at those currents.

-- Cheers, James Arthur

Gate tunneling currents. One can make some pretty good resistors in some very strange ways. ;-) ...not sure this circuit is going to work very well with bipolar transistors though.

Easier to make then you might think.

That nice black rubber Oldaker 600V rubber test lead wire..... About

How do I know?I used to work in lab that did applied electrostatics for 8 years. A zero to 30Kv supply and a Keithly electrometer and a pile of Oldaker wire and you can make what you need. My professor at the time, a vacuum tube curmudgeon, wanted some big resistors about 2 years ago for a sensor. I could not find 100 gig at any price, so I made them.

Hint, with care and a really good DMM and a 100 Meg resistor, you can dispense with the Keithley.

Steve

Gate tunneling is real too. Need an accurate voltage divider on CMOS?

Yes. How accurate? How predictable? ...Jim Thompson

From Digikey of course:

Dave.

Depends only on gate area, which is controlled pretty damned well.

The ones I have are glass encapsulated hermetically sealed types, around

Even if you can get them in 0805, the same rules would apply and they would only be usefull inside sealed units. Solder them on to a open pcb and lose half the resistance through leakage...

Regards,

Chris

Are you speaking through experience, or making that up?

Which one will lose half its resistance, the 100G or the 1T? Or both?

They come in 0603, too.

John

Not from experience probably.

I use 100M a lot in 0603 size, in designs going up to 125°C. I also used 5G in 0805 size, all without loosing nothing... Oh and those resistors are paralleled with 0402 & 0603 ceramics.

The only constrain is to be careful about cleaning and taking adequate precautions while routing.