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G8MNY > TECH 11.01.25 11:28l 39 Lines 1204 Bytes #999 (0) @ WW
BID : 23512_GB7CIP
Subj: Splitting a floating PSU
Path: IZ3LSV<I0OJJ<LU4ECL<VK2RZ<KC9UHI<KA1VSC<GB7CIP
Sent: 250111/1026Z @:GB7CIP.#32.GBR.EURO #:23512 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (New Aug 06)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
Here is a simple way to spit a single floating power supply into +/- rails. It
can be for any voltage 6V-100V to give ñ3V to ñ50V.
ÚÄÄÄÄÄÄÄÄ¿ +
³ ÃÄÄÄÄÂÄÄÄÄÂÄÄÄ>+ve
³Floating³ 1K ³/
³ ³ ÃÄÄ´NPN
³ Power ³ _³_ ³\e
³ ³ D1\_/ ÃÄÄÄ>0V
³ Supply ³ ³ ³/e
³ ³ ÃÄÄ´PNP
³ ³ 1K ³\
³ ÃÄÄÄÄÁÄÄÄÄÁÄÄÄ>-ve
ÀÄÄÄÄÄÄÄÄÙ -
The asymmetrical currents & voltages will affect the components needed (e.g.
transistors have to handle peak offset current & heat), in some applications,
e.g. value of 1K R may be 39K on 100V. Higher currents may need darlingtons or
P & N ch MOSFETs.
The above circuit should provide adequate balance for testing most things that
need a balanced supply.
D1 provides some cross over bias keeping the transistors in class B, 2 diodes
in series may do better, but easy to get into class AB/A & get hot when this is
not needed!
Y Don't U send an interesting bul?
73 de John G8MNY @ GB7CIP
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