Current reality check

[Jonathan Peakall]

Hi All,

 

I am making some colons for my latest clock with an NE-96. The suggested current for this is .5 mA. So, using a calculator, with an input of 200V, I should need around 240K for the anode resistor. Measuring the voltage across the resistor I see a voltage of around 120V. So, 240,000/120 = .0005. Perfect. The rub is that measuring the actual current with my meter show 5 mA, not .5 mA. So which is right? I hope it's me doing something stupid or I need another meter

 

Jonathan
www.madlabs.info

[David Forbes]

> www.madlabs.info <http://www.madlabs.info>

Your current meter is connected in *series* with the resistor and neon
tube, correct?


--
David Forbes, Tucson AZ

[Jonathan Peakall]

Yup. Otherwise the bulb would glow real bright and probably for a short
time. The glow with 240k *seems* reasonable.

[David Forbes]

Well, it's impossible to get 5ma to flow in that circuit, if the
resistor is the correct value. So check your meter on a lower voltage
circuit to be sure it's working right.

[threeneurons]

Your resistor okay ? Red-Yellow-Yellow ? Old carbon comp that you've had for 30 years ? Old meter, and "dp" in that location failed ? 200V thru a 240K resistor, all by itself, can't be more than 830uA. Somethings broken. Either meter or resistor.

[Jonathan Peakall]

You called it. Old eyes, wrong resistor. *embarrassed, shuffles off to corner muttering about the good old days*

 

Thanks!

--
You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/ABbX59ou8wcJ.
To post to this group, send an email to neoni...@googlegroups.com.
To unsubscribe from this group, send email to neonixie-l+...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.

[Mich...@aol.com]

Ahhhh, but think about how much time you saved having someone else discovered it for you.

 

I have learned..... I just ask my young son.  He is google king.  So, he thinks I'm an idiot, I think he's a generous, and I have my answer a lot faster than I would have been able to find it myself.

 

Michail

[threeneurons]

It only came to mind, because its a problem I've had for the last 10 years. I have a hard time distinguishing a 4.7K (yel-violet-red) from a 47K (yel-violet-org). I usually have to get out my meter. Both my eyes have become worse, and the vendors have gotten cheap with the paint.

[Instrument Resources of America]

I can still do o.k. reading the color codes with my bifocals, if the light is bright enough. If the light's not bright enough then out comes the magnifying glass, or the head magnifiers. Thank you harbor Freight Tools.   Ira

--

You received this message because you are subscribed to the Google Groups "neonixie-l" group.

To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/NZoR6JZ-CPIJ.