Continuity Test voltage 2.9 volts or 0.44 volts, LRC meter with ext. power supply

[danny davis]

My Fluke meter 87 Continuity checker mode test voltage is 2.9 volts
My Fluke 70 III Continuity Checker mode test voltage is 2.5 volts
My Craftsman meter Continuity Checker mode test voltage is at 0.443 volts

When a Continuity Test voltage is at 2.9 volts , what advantage does it have , over my Craftmans Continuity test voltage which is at 0.443?

Why would u want a Continuity test voltage at 2.9 volts?


An LCR meter when measuring Capacitors , test voltage is zero volts in some settings and others settings its 3 volts

Can I hook up an external power supply and set the power supply to the voltage rating of the capacitor and use the LCR meter in parallel to measure the capacitance of the capacitor at the voltage rating using WITH an ext. power supply? or will this damage the LCR meter>?

 

[Audioguru]

Why do you want to power a capacitor and measure its capacitance AT THE SAME TIME?? It will blow up the meter and even if it didn't destroy the meter then the capacitance will be shorted by the very low impedance power supply.

 

[danny davis]

Why do you want to power a capacitor and measure its capacitance AT THE SAME TIME?? It will blow up the meter and even if it didn't destroy the meter then the capacitance will be shorted by the very low impedance power supply.

Because an LCR meter doesn't test the capacitor at the voltage rating

A Capacitance tester , tests the capacitor at higher voltages, and at the voltage rating of the capacitor

Why would the capacitor be shorted by the low impedance power supply?

They put capacitors in parallel all the time in power supplies and they don't short because the power supply is low impedance

 

[Audioguru]

What fault do you expect to happen to a capacitor when it is charged to its voltage rating? Probably too much DC leakage current. The capacitance tester makes this test by itself.
An LCR tester tests the value of a capacitor when it is not connected to anything else. Connecting the LCR meter to a power supply will destroy the meter.

 

[danny davis]

What fault do you expect to happen to a capacitor when it is charged to its voltage rating? Probably too much DC leakage current. The capacitance tester makes this test by itself.

Yes, So why can't an LCR meter be connected in parallel to a power supply , isn't that what a capacitor meter is internally that capacitor meter that test capacitors at there voltage ratings

I'm trying to modify my LCR meter to be like a capacitor meter that can test cap at their voltage rating, how can I do this please? So i can test the capacitors leakage?

An LCR meter has no test voltage output on the Meter? it test the Capacitor at NO test voltage or current? or it's very low between 1 to 3 volts?

Connecting the LCR meter to a power supply will destroy the meter.

Why will it destroy the meter? how can i Modify the meter so it doesn't get damaged?

- - - Updated - - -

When a Continuity Test voltage is at 2.9 volts , what advantage does it have , over my Craftmans Continuity test voltage which is at 0.443?

Why would u want a Continuity test voltage at 2.9 volts?

I need help on knowing the difference between the two different kinds of test voltage of Continuity

 

[Audioguru]

You are supposed to measure the leakage current of a capacitor with a capacitor tester. It uses its own power supply voltage.
You are supposed to test the capacitance of a capacitor with an LCR tester. The capacitor must not be connected to anything else, especially not connected to a power supply.

One continuity meter has a test voltage of 0.443V. The other continuity tester has a test voltage of 2.9V.
Do you know which one will forward-bias a silicon diode and make the resistance appear to be lower than it is?

Why is the voltage only 0.2V on your Fluke meter when it measures Ohms?
Why is the voltage much higher, maybe 4V on your Fluke meter for Diode Test?

 

[betwixt]

I suppose the more basic question is: "why do you think the capacitance should be different at it's rated voltage than at zero volts?"

I accept I am ignoring some basic physics and chemistry here but the value should more or less be the same. Danny, do you think the LCR meter measures capcitance using DC or AC and why?

Brian.

 

[danny davis]

why do you think the capacitance should be different at it's rated voltage than at zero volts?"

It's not about the capacitor value, it's about measuring the leakage at the rated voltage

How do you measure capacitance leakage? when an LCR meter?

do you think the LCR meter measures capcitance using DC or AC and why?

The LCR on some setting has DC test voltage on the output but it's in the millivolts or 1 to 3 volts DC

It doesn't take capacitors with an AC test signal or voltage on the LCR meter

- - - Updated - - -

One continuity meter has a test voltage of 0.443V. The other continuity tester has a test voltage of 2.9V.
Do you know which one will forward-bias a silicon diode

The Test voltage 2.9 will turn on and conductor a diode or transistor or Logic gate

and make the resistance appear to be lower than it is?

No I don't know what u mean , what example ?

Why is the voltage only 0.2V on your Fluke meter when it measures Ohms?

Millivolts powering the resistor will conduct the resistor in a safe zone so it doesn't damage the resistor , a resistor just needs small current

Why is the voltage much higher, maybe 4V on your Fluke meter for Diode Test?

It's not 4 volts, it's 2.9 volts , my craftsman meter is 1.4 volts in diode tester

I'm not sure why they use 2.9 volts , maybe to test what kind of diodes?

- - - Updated - - -

One continuity meter has a test voltage of 0.443V. The other continuity tester has a test voltage of 2.9V.

The Fluke 87 continuity test outputs 2.9 volts, in continuity mode, this WILL turn on diodes, logic Gates Inputs and outputs, turn on transistors, turns on semiconductors

Craftmans meter continuity test outputs 0.4 volts, in continuity mode, this WON'T and Will not turn on diodes, logic Gates Inputs and outputs, turn on transistors, turns on semiconductors

OHMS mode test voltage is 0.2 volts, so you can't turn on semiconductors or Logic Gates inputs and outputs

- - - Updated - - -

I don't get why FLUKE meters want 2.9 volts for continuity test? for what reason?

It can turn on semiconductors and Logic gates inputs and outputs, why would u want 2.9 volts in continuity testing mode?

I don't get it

 

[Audioguru]

Why should I explain anything when you know NOTHING about electronics. I talk and type in an electronics GEEK language that you do not understand.

 

[danny davis]

I do understand it, i just don't know the info on it, that's why i ask

just explain it and i'll read it

 

[Audioguru]

Find out if a polarized electrolytic capacitor should be tested with AC or tested with AC on a DC bias voltage. Doesn't the LCR tester have a 3VDC setting for polarized capacitors?

Find out the voltage that forward-biases an LED and causes to light. List the different voltages of the colors. Doesn't your Continuity tester and diode test have 2.9V?
Find out the forward base-emitter voltage of a darlington transistor.

 

[danny davis]

Find out if a polarized electrolytic capacitor should be tested with AC or tested with AC on a DC bias voltage. Doesn't the LCR tester have a 3VDC setting for polarized capacitors?

No my BK or Tenma LRC meters don't have that option

Find out the voltage that forward-biases an LED and causes to light.

More than 2.9 volts test voltage that DVM meter , it needs 4 volts plus a series current resistor to not burn out the LED

I use a Huntron 2000 at work to test the LED in all colors , not a DVM meter

Which DVM meter test LED lights?

Doesn't your Continuity tester and diode test have 2.9V?

Only the FLUKE 87 at work , my craftmans is 1.4 volts in diode and continuity it's 0.4

I don't know why FLUKE 87 uses 2.9 for diodes and continuity, what advantages does it have?

Continuity what component or what , for the test voltage to be 2.9 volts?

Find out the forward base-emitter voltage of a darlington transistor.

.7 X 2 = 1.4 volts

 

[Audioguru]

On Diode Test, my Fluke meter dimly lights any color LED. Its display shows the forward voltage with a maximum of 4.0V. The current is limited so the LED does not burn out.

 

[danny davis]

the DVM meter can't test the different color lights, only the huntron 2000 can , i tried it

Back to my questions

One continuity meter has a test voltage of 0.443V. The other continuity tester has a test voltage of 2.9V.
The Fluke 87 continuity test outputs 2.9 volts, in continuity mode, this WILL turn on diodes, logic Gates Inputs and outputs, turn on transistors, turns on semiconductors

Craftmans meter continuity test outputs 0.4 volts, in continuity mode, this WON'T and Will not turn on diodes, logic Gates Inputs and outputs, turn on transistors, turns on semiconductors

OHMS mode test voltage is 0.2 volts, so you can't turn on semiconductors or Logic Gates inputs and outputs

- - - Updated - - -

I don't get why FLUKE meters want 2.9 volts for continuity test? for what reason?

It can turn on semiconductors and Logic gates inputs and outputs, why would u want 2.9 volts in continuity testing mode?

I don't get it

 

[danny davis]

Can I charge up a capacitor using an ext. power supply to it's power rating and then measure the capacitance using an LCR meter? but how can i measure the leakage?

 

[Audioguru]

Do you have a tester that tests how much beer the charged capacitor leaks??

 

[danny davis]

I just found out how to test the leakage current of a cap, so you can joke all your want about it

 

[betwixt]

don't keep us in suspense... how much beer did it leak.

Brian.

 

[danny davis]

You charge the capacitor to it's voltage rating and then measure the current in series using a ammeter in series with the voltage source still applied to the full charge cap.

A good cap, will have zero current at fully charge voltage rating
A bad cap, will have uA microamps of current at fully charge voltage rating

 

[betwixt]

An IDEAL capacitor will have zero current, real ones always have some leakage although it can be very tiny.
A bad capacitor has excessive leakage, more than the manufacturer has specified.

But - for once you got the test procedure right - whoopee!

Brian.