Dosimeter Charger

C

Chris UK

Guest
I've got an old pen-type dosimeter, and I've been googling for hours
trying to find charging/calibrating details.

As far as I have found, the charge voltage is (apparently) around 200
volts, and is basically an electrostatic charge.

So if I rectify and smooth the mains (UK 240V) and apply it to a high
value (1M or more) pot, with a 10M resistor from the wiper connected
to the dosimeter charging pin, and the neutral to the body of the
dosimeter, will it work?

(Disclaimer - I've worked in electronics for 35 years, and I am not
about to be electrocuted now. I just can't find enough parameter
information.)

TIA Chris
 
Chris UK <uk@heterodox.co.uk> wrote in message news:<6nfa90ltb1danbr6gcvpfldncqfv1810pb@4ax.com>...
I've got an old pen-type dosimeter, and I've been googling for hours
trying to find charging/calibrating details.

As far as I have found, the charge voltage is (apparently) around 200
volts, and is basically an electrostatic charge.

So if I rectify and smooth the mains (UK 240V) and apply it to a high
value (1M or more) pot, with a 10M resistor from the wiper connected
to the dosimeter charging pin, and the neutral to the body of the
dosimeter, will it work?

(Disclaimer - I've worked in electronics for 35 years, and I am not
about to be electrocuted now. I just can't find enough parameter
information.)
Click to expand...
Yup, I think the basic principle is to "zero" it by charging to a set voltage.

-A

TIA Chris
Click to expand...
 
On Sun, 02 May 2004 19:58:04 +0100, Chris UK <uk@heterodox.co.uk>
wrote:

I've got an old pen-type dosimeter, and I've been googling for hours
trying to find charging/calibrating details.

As far as I have found, the charge voltage is (apparently) around 200
volts, and is basically an electrostatic charge.

So if I rectify and smooth the mains (UK 240V) and apply it to a high
value (1M or more) pot, with a 10M resistor from the wiper connected
to the dosimeter charging pin, and the neutral to the body of the
dosimeter, will it work?

(Disclaimer - I've worked in electronics for 35 years, and I am not
about to be electrocuted now. I just can't find enough parameter
information.)

TIA Chris
Click to expand...
Sounds about right - I have a hand-cranked charger for them in a box
somewhere. If memory serves, it generates about 200V AC then rectifies
and current-limits it. Nice little thing! Voltage regulation wasn't
much to write home about (non-existent?), so it should work OK with
rectified mains.

Rick.
 
The Web site for surplustuff.com shows quite a bit of radiological
equipment for sale, including some dosimeter manuals. It sounds like
the site proprietor has first-hand experience operating and repairing
this gear as well. Maybe an email will get your question answered.

http://www.surplustuff.com/radiolog.html

--

Paul Hirose <ewwb4-khh25@earINVALIDthlink.net>
To reply by email delete INVALID from address.
 
On 2 May 2004 16:19:19 -0700, testing_h@yahoo.com (Andre) wrote:


Yup, I think the basic principle is to "zero" it by charging to a set voltage.
Click to expand...
Where I work, I don't think there is any attempt to zero the
dosimeters - they are just reset to some low reading periodically.
When someone signs out a dosimeter, he records the current reading,
then records the reading when he returns it - the difference is the
dose he received.


--
Peter Bennett VE7CEI
email: peterbb4 (at) interchange.ubc.ca
GPS and NMEA info and programs: http://vancouver-webpages.com/peter/index.html
Newsgroup new user info: http://vancouver-webpages.com/nnq
 
Chris UK <uk@heterodox.co.uk> wrote in message news:<6nfa90ltb1danbr6gcvpfldncqfv1810pb@4ax.com>...
I've got an old pen-type dosimeter, and I've been googling for hours
trying to find charging/calibrating details.

As far as I have found, the charge voltage is (apparently) around 200
volts, and is basically an electrostatic charge.

So if I rectify and smooth the mains (UK 240V) and apply it to a high
value (1M or more) pot, with a 10M resistor from the wiper connected
to the dosimeter charging pin, and the neutral to the body of the
dosimeter, will it work?

(Disclaimer - I've worked in electronics for 35 years, and I am not
about to be electrocuted now. I just can't find enough parameter
information.)

TIA Chris
Click to expand...
Right, it's roughly 200-250 volts.

A while back I unwisely purchased 100 dosimeter readout/chargers. If
you want one, I'd gladly mail it to you for $10 (US).

Harry C.
 
On Mon, 03 May 2004 14:21:48 +0100, Captain Rick wrote:

On Sun, 02 May 2004 19:58:04 +0100, Chris UK <uk@heterodox.co.uk
wrote:

I've got an old pen-type dosimeter, and I've been googling for hours
trying to find charging/calibrating details.

As far as I have found, the charge voltage is (apparently) around 200
volts, and is basically an electrostatic charge.

So if I rectify and smooth the mains (UK 240V) and apply it to a high
value (1M or more) pot, with a 10M resistor from the wiper connected
to the dosimeter charging pin, and the neutral to the body of the
dosimeter, will it work?

(Disclaimer - I've worked in electronics for 35 years, and I am not
about to be electrocuted now. I just can't find enough parameter
information.)

TIA Chris

Sounds about right - I have a hand-cranked charger for them in a box
somewhere. If memory serves, it generates about 200V AC then rectifies
and current-limits it. Nice little thing! Voltage regulation wasn't
much to write home about (non-existent?), so it should work OK with
rectified mains.

Rick.
Click to expand...
Just a folow-on to what has been said so far... Your mains voltage is
240 volts RMS, after rectifying and filtering it will almost be at the
peak voltage which is 1.414 times the RMS voltage - about 340 volts.
This might be too much for the dosimeter.

--

Tony Newman <tonyn@efn.org>
Springfield, OR
USA
 
I found this schematic inside my CD V-750 dosimeter charger. It's
old, but FWIW, here it is.



On Sun, 02 May 2004 19:58:04 +0100, Chris UK <uk@heterodox.co.uk>
wrote:

I've got an old pen-type dosimeter, and I've been googling for hours
trying to find charging/calibrating details.

As far as I have found, the charge voltage is (apparently) around 200
volts, and is basically an electrostatic charge.

So if I rectify and smooth the mains (UK 240V) and apply it to a high
value (1M or more) pot, with a 10M resistor from the wiper connected
to the dosimeter charging pin, and the neutral to the body of the
dosimeter, will it work?

(Disclaimer - I've worked in electronics for 35 years, and I am not
about to be electrocuted now. I just can't find enough parameter
information.)

TIA Chris
Click to expand...
If God hadn't intended us to eat animals,
He wouldn't have made them out of MEAT!
- John Cleese
 
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