Malfunctioning meter.: https://youtu.be/xNy8IOlRkII Compilation below from the Electric Vehicle Discussion List.
It is clearly the sun causing the problem. Some years ago I was designing
RFID readers for cow tags, I found that the tags themselves were sensitive
to sunlight! In fact, any chip that does not have sunlight positively
excluded is.... this meter will probably have a chip bonded to the bottom of
the pcb directly with a blob of sealer on the top.
RFID readers for cow tags, I found that the tags themselves were sensitive
to sunlight! In fact, any chip that does not have sunlight positively
excluded is.... this meter will probably have a chip bonded to the bottom of
the pcb directly with a blob of sealer on the top.
Electronic circuits (The silicon wafer that carries the transistors and other circuitry)
is affected in its operation by light. Similar to a solar cell generating current when hit
by photons, also a slice of silicon for a transistor or other electronic component will start
generating a small current under light, so it is a sign that the actual chip of the meter,
which normally is potted in a black blob for this reason, is not completely potted and is receiving
enough light to be affected by the (stray) light falling on it.
It is the electronics that is affected by light (photons), not the LCD or the heat.
Cor van de Water
Chief Scientist
Proxim Wireless
is affected in its operation by light. Similar to a solar cell generating current when hit
by photons, also a slice of silicon for a transistor or other electronic component will start
generating a small current under light, so it is a sign that the actual chip of the meter,
which normally is potted in a black blob for this reason, is not completely potted and is receiving
enough light to be affected by the (stray) light falling on it.
It is the electronics that is affected by light (photons), not the LCD or the heat.
Cor van de Water
Chief Scientist
Proxim Wireless
Message: 7
Date: Tue, 17 Mar 2015 19:58:25 -0400
From: Mark Grasser via EV <ev@lists.evdl.org>
To: "'Electric Vehicle Discussion List'" <ev@lists.evdl.org>
Subject: Re: [EVDL] Watch "Malfunctioning meter." on YouTube
Message-ID: <000001d0610e$423636b0$c6a2a410$@com>
Content-Type: text/plain; charset="iso-8859-1"
I would suspect that sunlight on the display raises the current draw of the
display. This current draw is on the 5 volt regulator of the entire meter.
Being an inexpensive meter the 5 volt regulator is also the reference
voltage for the meter. Current goes up, reference voltage goes down.
Reference voltage goes down and the reading goes up.
Sincerely,
Mark Grasser -
Date: Tue, 17 Mar 2015 19:58:25 -0400
From: Mark Grasser via EV <ev@lists.evdl.org>
To: "'Electric Vehicle Discussion List'" <ev@lists.evdl.org>
Subject: Re: [EVDL] Watch "Malfunctioning meter." on YouTube
Message-ID: <000001d0610e$423636b0$c6a2a410$@com>
Content-Type: text/plain; charset="iso-8859-1"
I would suspect that sunlight on the display raises the current draw of the
display. This current draw is on the 5 volt regulator of the entire meter.
Being an inexpensive meter the 5 volt regulator is also the reference
voltage for the meter. Current goes up, reference voltage goes down.
Reference voltage goes down and the reading goes up.
Sincerely,
Mark Grasser -
-----Original Message-----
From: EV [mailto:ev-bounces@lists.evdl.org] On Behalf Of Lawrence Rhodes via
EV
Sent: Wednesday, 18 March 2015 10:56 a.m.
To: Electric Vehicle Discussion List
Subject: [EVDL] Watch "Malfunctioning meter." on YouTube
Malfunctioning meter.: https://youtu.be/xNy8IOlRkII
This is the correct url. Lawrence Rhodes
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Posted by: Lawrence Rhodes <primobassoon@sbcglobal.net>
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