Message 25870 in TECH.GBR
From: G8MNY
Date: Tue, 14 Jul 26 06:38:00 Z
Newsgroups: TECH.GBR
Subject: Maplin Mains Meter 2000MU-UK
Message-ID: <64893_GB7CIP>
Path: GB7RJJ|GB7OSW|GB7BED|GB7CIP
R:260714/0933Z 16661@GB7RJJ.#79.GBR.EURO LinBPQ6.0.25
R:260714/0644Z 44155@GB7OSW.#16.GBR.EU LinBPQ6.0.25
R:260714/0644Z 14283@GB7BED.#21.GBR.EU LinBPQ6.0.25
R:260714/0638Z @:GB7CIP.#32.GBR.EURO #:64893 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@GBR
By G8MNY (Updated Mar 10)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
This plug in meter is made by Prodiget Electronics Co for Maplin.
It measures true RMS:- Frequency, Voltage, Current, VA, Power Factor, & kWHrs
to quite a high accuracy. Current over 16A sounds an alarm.
PRINCIPLE
Once in digital form, the instantaneous voltage & currents can easily be number
crunched in the uProc to measure & display the Voltage, Current, Frequency,
True RMS power Watts, VA, Power Factor, & kW Hours.
CIRCUIT
Mains Mains
Plug Socket
N L N L
IMPROVEMENTS
1/ The unit is not to be used outdoor (not water proof) & the internals are
live. I syringed in "copydex" rubber solution over all the case joints &
cracks, including the plug, socket & LCD surround. Although not perfectly
water proof it is a lot safer in outdoor use.
2/ R18 100R 5W surge R came unsoldered when measuring inverter square wave.
This ensures less peak current on non sine wave sources. I also added a
solder tags as a heatsinks to each end of the 17V zener connections.
3/ Added a small white LED to the side of the LCD, with a tin foil as opposite
end reflector. The 3.5V LED runs across the zener supply via a 1k. So the
meter is usable at night. This also indicates if there is power, but the
uProc has crashed (needs repowering).
See my buls on "AC Theory", "Constant Voltage Transformers", "Variacs",
"Portable Appliance Testing", "UK 13A Fused mains plug", "Mains Power
Protection" & also "Maplin 13A Socket Mains Tester".
Why don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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