[Amps] Re: HV breakdown tester schematic

[Dennis12Amplify at aol.com]

In a message dated 10/16/03 10:22:23 PM Central Daylight Time, 
k8cu at ameritech.net writes:

> Hello Dennis,
> 
> I stumbled across your comments on the breakdown tester while viewing the
> Amps reflector archives.

>>> I was going to send you some email after Rich and Skip and some others >>>
verified what I thought I had found. I didn't want to critique you and be >>>
wrong, so I put what I found out for comments and rebuttal, but other >>>than 
Rich's answer about the bridge rectifier, I did not see any other >>>comments 
regarding my post.

> 
> It appears that there is an error in my schematic as shown on the web site.
> As you mentioned, the current drop across the series limiting resistor will
> reduce the actual voltage applied to the tested device, and this reduced
> voltage will not be measured by the voltmeter. A fix for this is to actually
> measure the voltage at the device by placing the output voltage meter and
> associated scaling resistors AFTER the current limiting resistor.


 >>> And save some resistors by using the current limiting resistors as part 
of >>> the scaling resistor string!.

> 
> I will make this change on the schematic.  Thanks for your attention to
> detail.
> 
> Bill Jones, K8CU
> www.realhamradio.com
> 
> PS What is your full name and callsign?


>>> Dennis W. Ostrowski

>>>Ham license expired back in 1964 or so and I never renewed it.

>>>Got a 1st class Radiotelegraph license instead, P1-18-46767, which was >>>
later converted to a lifetime General.

 I can make a credit note in the website article.

>>>Not necessary, as a matter of fact I would prefer you didn't.

>>> It's easy to critique someone else's work but it takes guts to design >>>
something and then publish it to the entire world. Therefore you should >>>
still get full credit for what was a good and original design. 

>>>I was just doing what I had done for my last 12 years at Lucent >>>
Technologies before being prematurely 'retired'. I would be the last >>>engineer to 
critique most new hardware designs before they went into >>>production.

>>> I had read the good comments about the tester so I went to the website >>>
to see what I would have to purchase to put one together; and just >>>
happened to notice the problem with the voltage drop across those series >>>current 
limiting resistors.

>>>Just make the change and pass the word around to those who have built >>>
them and are using them. If they want to continue to use the tester as-is, >>>
tell them to increase the voltage till the 50 microamp leagage current >>>meter 
just barely starts to move. 
>>>The applied voltage error factor would be minimized in that scenario.

>>>You can also remove that bridge rectifier across the leakage meter unless >
>>you want to start making AC leakage tests, but if you plan to do that, then 
>>>you will have to add a bridge rectifier across the applied voltage meter.

 >>> Regards,

>>>Dennis O.
>>>Astro Electronics
>>>Frankfort, Illinois