[volt-nuts] Precision high resistance measurements / calibration of HP 4339B high-resistance meter.

I pickup up an HP/Agilent (front says HP, rear says Agilent) 4339B high-resistance meter from eBay. The 4339B has an internal supply up to 1000 V, an ammeter to measure current, and obviously computes resistance from Ohms Law. It is supposed to work up to 16 Peta ohms (1.6x10^16 ohms), which would

Re: [volt-nuts] LM3900

Attila wrote: Theoretically yes, in practice you are better off using an opamp that is not 40 years old and not as quirky as a Norton opamp. They are also perhaps the noisiest op-amps ever marketed. They invite one to add the missing PNP differential input pair externally, but even this is

Re: [volt-nuts] LM3900 (was: HP3458 ADC integrator) Instrumentation Amplifiers (3)

Hi, also have three AD623(?) IA's I purchased for a heart rate monitor. Can find them as and when needed, pretty sure they are the ones featured in the Hackaday article. At the time if the ECG worked the same circuit would get cloned and used for an EEG as the signals are a lot smaller but in

[volt-nuts] LM3900 (was: HP3458 ADC integrator)

On Wed, 28 Feb 2018 06:32:58 + Andre wrote: > Can you make use of an LM3900? I have one here *somewhere*. > I think its a quad Norton, not sure how long its been there for. Theoretically yes, in practice you are better off using an opamp that is not 40 years old and not as