Re: [volt-nuts] Ayrton Shunt does double duty.

The volt box is likely to be a voltage divider that was used to divide a voltage to be measured down to a value within the measurement range of a L & N potentiometer (not the 3 terminal component but the type that sets up the current in a series string of resistors to a known vale by comparing

Re: [volt-nuts] How can I make a 2000 V DC meter with an input resistance of at least 100 T ohms?

Vibrating capacitor non contact field probe in feedback loop to create a voltage follower: https://www.monroe-electronics.com/ESD/pdf/244a_m.pdf Bruce > > On 23 March 2018 at 15:12 Neville Michie wrote: > > Improvise by holding a metal disk over an electronic

Re: [volt-nuts] How can I make a 2000 V DC meter with an input resistance of at least 100 T ohms?

Electrostatic voltmeter? Either the classical version or the modern electronic variant perhaps? Bruce > > On 23 March 2018 at 13:33 "Dr. David Kirkby" > wrote: > > I want to measure a high voltage, but put minimal load on the circuit. > Looking at

Re: [volt-nuts] Bohnenberger electrometer

A method in use 40+ odd years ago for measuring atmospheric electric fields was to use a slotted rotating disk rather than the rotating cylinder. A matching stationary or counter rotating disk IIRC was used either in front or behind the rotating slotted disk the the sensing disk was behind

Re: [volt-nuts] Vibrating reed electrometers

The Keithley model 640 was a vibrating capacitor electrometer. It was available in the 1970's. Bruce > > On 04 March 2018 at 06:34 george wrote: > > Hi all > > To the best of my memory Keithley never made vibrating reed > electrometers, the only one that I

Re: [volt-nuts] HP3458 ADC integrator

1) Reverse the supplies on U4 (in real circuit reversed supplies will fry the chip.) 2) Add 10k in series with reset switch 3) Swap connections to U4 inputs. 4) Use series shunt switch for reset switch as used in an actual 3458A. Once done together with swapping in LT1220 for LT1225 rest works as

Re: [volt-nuts] HP3458 ADC integrator

Why do you think that the datasheet is wrong? Its the same as the 1989 version. A lot of the early wideband opamps didn't have high open loop gain. Even the LT1220 only has about 7 - 15x more gain at rated load. The LT1220 has a a pair of cascaded complementary symmetry emitter followers in

Re: [volt-nuts] HP3458 ADC integrator

Attila Some insight can be gleaned by using a single pole model for an opamp configured as an integrator and deriving the expression for the output signal. Look at the non linearity in the output. Look at the voltage at the inverting input. The effective impedance at the inverting input due to

Re: [volt-nuts] HP3458 ADC integrator

08:45 Bruce Griffiths <bruce.griffi...@xtra.co.nz> > wrote: > > Moin attila > > I'd start with simulating and understanding the integrator in the 34401A, > its a little simpler but still has a coupe of opamps in the integrator. Then > analysing the GBW requir

Re: [volt-nuts] HP3458 ADC integrator

Moin attila I'd start with simulating and understanding the integrator in the 34401A, its a little simpler but still has a coupe of opamps in the integrator. Then analysing the GBW requirements of the various opamps used in the HP3458A shoul become somewhat clearer. Bruce > > On 24

Re: [volt-nuts] Prema 6048 zero offset problems

Result of nonlinearity and dc offset combined? Bruce > > On 19 January 2018 at 00:57 "David C. Partridge" > wrote: > > Starting with a warmed up Prema 6048, if I power it off and then on, > select > 20V DC range, 4 second integration and connect to

Re: [volt-nuts] PCBs with ceramic substrates

than using a constant dimension of fibers. > > > On Mon, 17 Apr 2017 05:35 Bruce Griffiths, <bruce.griffi...@xtra.co.nz > mailto:bruce.griffi...@xtra.co.nz > wrote: > > > > > > There's little out there on the frequency dependence of d

Re: [volt-nuts] PCBs with ceramic substrates

s, measured on a real world material? It would tell me a > lot. > > > On Mon, 17 Apr 2017 04:19 Bruce Griffiths, <bruce.griffi...@xtra.co.nz > mailto:bruce.griffi...@xtra.co.nz > wrote: > > > > > > Hook is merely a manifestation

Re: [volt-nuts] DAS-46

A CLD is merely a JFET with the gate connected to the source.Sometimes a source resistor may be included with the gate connected to the opposite end of the resistor to the end connected to the source. Bruce On Monday, 30 January 2017 12:12 PM, Jerry Hancock wrote:

Re: [volt-nuts] low emf solder

Laser welding should work for either similar or dissimilar materials.At one time microwire PCBs  used stainless steel  wires were welded to stainless lands. Bruce  On Saturday, 29 October 2016 1:39 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On

Re: [volt-nuts] Calibration of 34401A

Calibration of a 34401A is done electronically, however one needs to know the calibration security code.If unknown one needs to open the meter to enable calibration and then reassemble it and complete the calibration. The factory default calibration security code is HP034401 only 034401 need be

Re: [volt-nuts] Practical power supply noise testing

Its certainly a good way to quickly check if anythings drastically wrong and one could even compare them with a known source such as an LM317 based regulator with no ADJ pin bypass. If one can hear the noise then its possible that a sound card could make some meaningful measurements of the

Re: [volt-nuts] Practical power supply noise testing

I've used a pair of minicircuits phase modulators, a low noise OXCO, and a Timepod to do this.The phase modulators work best with about 9V input.The noise of my E3610A's is clearly evident as is the noise of an LM317 based regulator with unbypassed ADJ terminal.To achieve lower system noise a

Re: [volt-nuts] ADA4522

Why?The ADA4522 is unity gain stable with about 60 degrees of phase margin.The equivalent output inductance at unity gain is about 0.5u 50 ohms in series with the 1uF output capacitance ensures an overdamped response. Bruce On Saturday, 9 April 2016 11:20 PM, "acb...@gmx.de"

[volt-nuts] monitoring LTZ1000 chip temperature

In order to understand the dynamics of the LTZ1000 temperature regulation loop better in order to estimate the chip temperature response due to ambient temperature fluctuations, I am attempting to produce a model of the thermal impedance of the chip by fitting a Foster RC ladder (later

Re: [volt-nuts] Resistors for LTZ1000A circuit

Frank Stellmach wrote: Dave, well the schematic is the same as in the LT specification. My PCB is a prototype, and I would not like to publish it, because it contains several bugs. One one those bugs led to the first change of the initial LT specification, i.e. I discovered the parasitic diode

Re: [volt-nuts] Fluke 332D

Dick wrote: I need a little circuit help here -- I'm looking at the schematic of the chopper amp, A5A4, and I'm trying to figure out if this amp is inverting or non-inverting for DC signals, that is from pin 6 input to pin 4 output. I'm looking at the simplified diagram on page 102 of the PDF