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G8MNY > TECH 14.03.26 11:04l 46 Lines 1772 Bytes #60 (0) @ WW
BID : 54382_GB7CIP
Read: GUEST
Subj: Plug Top PS charge indicator
Path: ED1ZAC<ED1ZAC<LU4ECL<VK2RZ<GB7CIP
Sent: 260314/0954Z @:GB7CIP.#32.GBR.EURO #:54382 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (New Jan 21)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
Here is a circuit used in a small kit battery charger. The battery kit has a
battery disconnect feature when fully charged (thermal or voltage end point)
etc. and reduces the plug top load.
+20V off load 16V charging
ÚÄÄÄÄÄÂÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ>+V
³ ³ 10V_³_
³ ³ '/_\
L<ÄÂÄÄÄthÄÄ¿ __/+\_ ³ ÚÄÄÄÄ´
m22 fuse )||( ~\-/~³ ³ ³ 470R
neon )||( ³ ³ ³ 15K ÃÄÄÄÄ¿
³ )||( ³ ³ ³ ³ 680R _³_ CHARGED
N<ÄÁÄÄÄÄÄÄÄÙ ÀÄÄ)ÄÄÙ ³ ³ ³ \_/ð RED
³ +³ ³ ÃÄÄÄÄ´
³ 1m=== ³ ³/ _³_ CHARGING
³ 25V³ ÃÄÄ´NPN \_/ð GREEN
³ ³ 1K ³\e ³
ÀÄÄÄÄÄÁÄÄÄÁÄÄÄÄÁÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄ>-ve
It relies on the voltage drop of the simple PSU on load to work the indicator
electronics.
When load is off the voltage overcomes the zener drop and lights the LEDS. But
also turns on the NPN, shorting out the green LED.
When load is on, the voltage still overcomes the zener drop and lights the LEDS
But not enough to turns on the NPN, and the green LED lights and on the lower
voltage the 680R across the red LED stops it lighting.
If LEDs are not lit there is either no power or PSU is overloaded!
Adjustments for your PSU might be to make the 1K a 2K2 preset, and select the
zenner voltage for your PSU, so that at least 6V is avalable to the cicuit when
charging.
See my Tech Bul "Analyser SWIRES RESEARCH SA87"
Why don't U send an interesting bul?
73 de John, G8MNY @ GB7CIP
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