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Power supply topology question ...

Started by Unknown November 4, 2013
Could some electronics guru please shed 
some light on the following. The standard 
topology for a linear regulated power 
supply is basically as follows:
   isolation step-down transformer 
               |
               v
   rectifier(bridge or 2 - diode)
               |
               v
   capacitor ripple filter bank
               |
               v
   voltage regulator
               |
               v
   capacitor ripple filter bank
               |
               V
Let us suppose that the transformer is a 
step-down 9 - 0 - 9 1 Amp output device.

Now suppose I want to get two 1 Amp outputs
by having a 9 - 0 -9 2 Amp transformer and
splitting its output equally with resistors
as :
isolation step-down transformer 
      |                  |
      v                  v
  resistor 	      resistor
      |                  |
      V                  V
  rectifier etc.,      rectifier etc.,
Is this a valid topology ? Or should there
be two 9 - 0 - 9 1 Amp isolation transformers
connected to the common Ac wall input, and 
then parallel topology as above, without the
resistors.
Any thoughts, suggestions would be appreciated.
Thanks in advance.
 
On 2013-11-04, dakupoto@gmail.com <dakupoto@gmail.com> wrote:
> Could some electronics guru please shed > some light on the following. The standard > topology for a linear regulated power > supply is basically as follows:
> isolation step-down transformer > | > v > rectifier(bridge or 2 - diode) > | > v > capacitor ripple filter bank > | > v > voltage regulator > | > v > capacitor ripple filter bank > | > V
> Let us suppose that the transformer is a > step-down 9 - 0 - 9 1 Amp output device. > > Now suppose I want to get two 1 Amp outputs > by having a 9 - 0 -9 2 Amp transformer and > splitting its output equally with resistors > as :
a 9-0-9 2A transformer is probably sufficienctly oversized
> isolation step-down transformer > | | > v v > resistor resistor > | | > V V > rectifier etc., rectifier etc., > Is this a valid topology ? Or should there > be two 9 - 0 - 9 1 Amp isolation transformers > connected to the common Ac wall input, and > then parallel topology as above, without the > resistors. > Any thoughts, suggestions would be appreciated. > Thanks in advance.
use one transofrmer, one rectifier, and one input capacitor bank. double up the regulators and everything downstream. -- For a good time: install ntp --- news://freenews.netfront.net/ - complaints: news@netfront.net ---
On 11/3/2013 8:21 PM, dakupoto@gmail.com wrote:
> Could some electronics guru please shed > some light on the following. The standard > topology for a linear regulated power > supply is basically as follows: > isolation step-down transformer > | > v > rectifier(bridge or 2 - diode) > | > v > capacitor ripple filter bank > | > v > voltage regulator > | > v > capacitor ripple filter bank > | > V > Let us suppose that the transformer is a > step-down 9 - 0 - 9 1 Amp output device. > > Now suppose I want to get two 1 Amp outputs > by having a 9 - 0 -9 2 Amp transformer and > splitting its output equally with resistors > as : > isolation step-down transformer > | | > v v > resistor resistor > | | > V V > rectifier etc., rectifier etc., > Is this a valid topology ? Or should there > be two 9 - 0 - 9 1 Amp isolation transformers > connected to the common Ac wall input, and > then parallel topology as above, without the > resistors. > Any thoughts, suggestions would be appreciated. > Thanks in advance. > >
Draw the circuit with the ground/return(s). That, coupled with a clear definition/specification of your objective should give you the answer.
On Sun, 3 Nov 2013 20:21:46 -0800 (PST), dakupoto@gmail.com wrote:

>Could some electronics guru please shed >some light on the following. The standard >topology for a linear regulated power >supply is basically as follows: > isolation step-down transformer > | > v > rectifier(bridge or 2 - diode) > | > v > capacitor ripple filter bank > | > v > voltage regulator > | > v > capacitor ripple filter bank > | > V >Let us suppose that the transformer is a >step-down 9 - 0 - 9 1 Amp output device. > >Now suppose I want to get two 1 Amp outputs >by having a 9 - 0 -9 2 Amp transformer and >splitting its output equally with resistors >as : >isolation step-down transformer > | | > v v > resistor resistor > | | > V V > rectifier etc., rectifier etc., >Is this a valid topology ?
--- No. Neglecting the transformer's regulation, whether the transformer is rated 9V-0V-9V at 1 or 2 (or 100, for that matter) amperes, the load will only take what it needs since the secondary voltages are identical and the resistor will drop the voltage into the rectifiers depending on the load. ---
>Or should there >be two 9 - 0 - 9 1 Amp isolation transformers >connected to the common Ac wall input, and >then parallel topology as above, without the >resistors.
--- If you have a 2A transformer and 1A loads and you need to isolate the loads, a more sensible arrangement would be to run a separate FWB supply off of each secondary since 1A transformers will overheat if you're using capacitor input filters. ---
>Any thoughts, suggestions would be appreciated. >Thanks in advance. >
On Mon, 04 Nov 2013 05:55:27 -0600, John Fields
<jfields@austininstruments.com> wrote:


>--- >If you have a 2A transformer and 1A loads and you need to isolate >the loads, a more sensible arrangement would be to run a separate >FWB supply off of each secondary since 1A transformers will overheat >if you're using capacitor input filters. >---
Version 4 SHEET 1 880 920 WIRE -2000 -16 -2144 -16 WIRE -1632 -16 -1808 -16 WIRE -1440 -16 -1632 -16 WIRE -1632 16 -1632 -16 WIRE -1440 16 -1440 -16 WIRE -2000 112 -2000 -16 WIRE -1808 112 -1808 -16 WIRE -2144 128 -2144 -16 WIRE -1632 128 -1632 80 WIRE -1568 128 -1632 128 WIRE -1440 128 -1440 80 WIRE -1440 128 -1488 128 WIRE -1632 176 -1632 128 WIRE -1632 176 -1680 176 WIRE -1440 176 -1440 128 WIRE -1392 176 -1440 176 WIRE -1680 208 -1680 176 WIRE -1632 224 -1632 176 WIRE -1568 224 -1632 224 WIRE -1440 224 -1440 176 WIRE -1440 224 -1504 224 WIRE -1632 272 -1632 224 WIRE -1440 272 -1440 224 WIRE -2144 368 -2144 208 WIRE -2000 368 -2000 192 WIRE -2000 368 -2144 368 WIRE -1936 368 -2000 368 WIRE -1808 368 -1808 192 WIRE -1808 368 -1856 368 WIRE -1632 368 -1632 336 WIRE -1632 368 -1808 368 WIRE -1440 368 -1440 336 WIRE -1440 368 -1632 368 WIRE -1632 480 -1808 480 WIRE -1440 480 -1632 480 WIRE -1632 512 -1632 480 WIRE -1440 512 -1440 480 WIRE -1808 608 -1808 480 WIRE -1632 624 -1632 576 WIRE -1568 624 -1632 624 WIRE -1440 624 -1440 576 WIRE -1440 624 -1488 624 WIRE -1632 672 -1632 624 WIRE -1632 672 -1680 672 WIRE -1440 672 -1440 624 WIRE -1392 672 -1440 672 WIRE -1680 704 -1680 672 WIRE -1632 720 -1632 672 WIRE -1568 720 -1632 720 WIRE -1440 720 -1440 672 WIRE -1440 720 -1504 720 WIRE -1632 768 -1632 720 WIRE -1440 768 -1440 720 WIRE -2000 864 -2000 368 WIRE -1936 864 -2000 864 WIRE -1808 864 -1808 688 WIRE -1808 864 -1856 864 WIRE -1632 864 -1632 832 WIRE -1632 864 -1808 864 WIRE -1440 864 -1440 832 WIRE -1440 864 -1632 864 FLAG -1680 208 0 FLAG -1680 704 0 FLAG -1392 176 OUT1 FLAG -1392 672 OUT2 SYMBOL ind2 -2016 96 R0 WINDOW 0 45 47 Left 2 WINDOW 3 45 79 Left 2 SYMATTR InstName L1 SYMATTR Value 50 SYMATTR Type ind SYMATTR SpiceLine Rser=,1 SYMBOL voltage -2144 112 R0 WINDOW 3 24 104 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR Value SINE(0 170 60) SYMATTR InstName V2 SYMBOL ind2 -1792 208 R180 WINDOW 0 42 73 Left 2 WINDOW 3 48 42 Left 2 SYMATTR InstName L2 SYMATTR Value .5 SYMATTR Type ind SYMBOL res -1472 112 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName RL1 SYMATTR Value 16 SYMBOL diode -1456 16 R0 WINDOW 0 -38 34 Left 2 WINDOW 3 -98 -1 Left 2 SYMATTR InstName D3 SYMATTR Value MURS320 SYMBOL diode -1648 272 R0 WINDOW 0 -38 34 Left 2 WINDOW 3 -96 72 Left 2 SYMATTR InstName D2 SYMATTR Value MURS320 SYMBOL diode -1616 80 R180 WINDOW 0 42 34 Left 2 WINDOW 3 24 69 Left 2 SYMATTR InstName D1 SYMATTR Value MURS320 SYMBOL diode -1424 336 R180 WINDOW 0 42 32 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D4 SYMATTR Value MURS320 SYMBOL ind2 -1792 704 R180 WINDOW 0 40 67 Left 2 WINDOW 3 45 40 Left 2 SYMATTR InstName L3 SYMATTR Value .5 SYMATTR Type ind SYMBOL res -1472 608 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName RL2 SYMATTR Value 16 SYMBOL diode -1456 512 R0 WINDOW 0 -38 34 Left 2 WINDOW 3 -98 -1 Left 2 SYMATTR InstName D7 SYMATTR Value MURS320 SYMBOL diode -1648 768 R0 WINDOW 0 -38 34 Left 2 WINDOW 3 -96 72 Left 2 SYMATTR InstName D6 SYMATTR Value MURS320 SYMBOL diode -1616 576 R180 WINDOW 0 42 34 Left 2 WINDOW 3 24 69 Left 2 SYMATTR InstName D5 SYMATTR Value MURS320 SYMBOL diode -1424 832 R180 WINDOW 0 42 32 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D8 SYMATTR Value MURS320 SYMBOL res -1840 352 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 1G SYMBOL res -1840 848 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 1G SYMBOL polcap -1504 208 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 10000&#2013266101; SYMBOL polcap -1504 704 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10000&#2013266101; TEXT -2136 400 Left 2 !.tran 1 TEXT -1984 80 Left 2 !K1 L1 L2 L3 1 TEXT -2160 432 Left 2 ;JOHN FIELDS TEXT -2160 464 Left 2 ;04 OCT 2013
On Sun, 03 Nov 2013 20:21:46 -0800, dakupoto wrote:

> Could some electronics guru please shed some light on the following. The > standard topology for a linear regulated power supply is basically as > follows: > isolation step-down transformer > | > v > rectifier(bridge or 2 - diode) > | > v > capacitor ripple filter bank > | > v > voltage regulator > | > v > capacitor ripple filter bank > | > V > Let us suppose that the transformer is a step-down 9 - 0 - 9 1 Amp > output device. > > Now suppose I want to get two 1 Amp outputs by having a 9 - 0 -9 2 Amp > transformer and splitting its output equally with resistors as : > isolation step-down transformer > | | > v v > resistor resistor > | | > V V > rectifier etc., rectifier etc., > Is this a valid topology ? Or should there be two 9 - 0 - 9 1 Amp > isolation transformers connected to the common Ac wall input, and then > parallel topology as above, without the resistors. > Any thoughts, suggestions would be appreciated. > Thanks in advance.
The resistors are unnecessary. If you don't need it to be isolated, just make a 2A supply and hook the loads up in parallel. I think you fail to understand the distinction between the current _rating_ on a supply and the current drawn by a load at a particular voltage, but I'm not sure. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
On Monday, November 4, 2013 10:17:57 AM UTC-5, John Fields wrote:
> On Mon, 04 Nov 2013 05:55:27 -0600, John Fields >=20 > <jfields@austininstruments.com> wrote: >=20 >=20 >=20 >=20 >=20 > >--- >=20 > >If you have a 2A transformer and 1A loads and you need to isolate >=20 > >the loads, a more sensible arrangement would be to run a separate >=20 > >FWB supply off of each secondary since 1A transformers will overheat >=20 > >if you're using capacitor input filters. >=20 > >--- >=20 >=20 >=20 > Version 4 >=20 > SHEET 1 880 920 >=20 > WIRE -2000 -16 -2144 -16 >=20 > WIRE -1632 -16 -1808 -16 >=20 > WIRE -1440 -16 -1632 -16 >=20 > WIRE -1632 16 -1632 -16 >=20 > WIRE -1440 16 -1440 -16 >=20 > WIRE -2000 112 -2000 -16 >=20 > WIRE -1808 112 -1808 -16 >=20 > WIRE -2144 128 -2144 -16 >=20 > WIRE -1632 128 -1632 80 >=20 > WIRE -1568 128 -1632 128 >=20 > WIRE -1440 128 -1440 80 >=20 > WIRE -1440 128 -1488 128 >=20 > WIRE -1632 176 -1632 128 >=20 > WIRE -1632 176 -1680 176 >=20 > WIRE -1440 176 -1440 128 >=20 > WIRE -1392 176 -1440 176 >=20 > WIRE -1680 208 -1680 176 >=20 > WIRE -1632 224 -1632 176 >=20 > WIRE -1568 224 -1632 224 >=20 > WIRE -1440 224 -1440 176 >=20 > WIRE -1440 224 -1504 224 >=20 > WIRE -1632 272 -1632 224 >=20 > WIRE -1440 272 -1440 224 >=20 > WIRE -2144 368 -2144 208 >=20 > WIRE -2000 368 -2000 192 >=20 > WIRE -2000 368 -2144 368 >=20 > WIRE -1936 368 -2000 368 >=20 > WIRE -1808 368 -1808 192 >=20 > WIRE -1808 368 -1856 368 >=20 > WIRE -1632 368 -1632 336 >=20 > WIRE -1632 368 -1808 368 >=20 > WIRE -1440 368 -1440 336 >=20 > WIRE -1440 368 -1632 368 >=20 > WIRE -1632 480 -1808 480 >=20 > WIRE -1440 480 -1632 480 >=20 > WIRE -1632 512 -1632 480 >=20 > WIRE -1440 512 -1440 480 >=20 > WIRE -1808 608 -1808 480 >=20 > WIRE -1632 624 -1632 576 >=20 > WIRE -1568 624 -1632 624 >=20 > WIRE -1440 624 -1440 576 >=20 > WIRE -1440 624 -1488 624 >=20 > WIRE -1632 672 -1632 624 >=20 > WIRE -1632 672 -1680 672 >=20 > WIRE -1440 672 -1440 624 >=20 > WIRE -1392 672 -1440 672 >=20 > WIRE -1680 704 -1680 672 >=20 > WIRE -1632 720 -1632 672 >=20 > WIRE -1568 720 -1632 720 >=20 > WIRE -1440 720 -1440 672 >=20 > WIRE -1440 720 -1504 720 >=20 > WIRE -1632 768 -1632 720 >=20 > WIRE -1440 768 -1440 720 >=20 > WIRE -2000 864 -2000 368 >=20 > WIRE -1936 864 -2000 864 >=20 > WIRE -1808 864 -1808 688 >=20 > WIRE -1808 864 -1856 864 >=20 > WIRE -1632 864 -1632 832 >=20 > WIRE -1632 864 -1808 864 >=20 > WIRE -1440 864 -1440 832 >=20 > WIRE -1440 864 -1632 864 >=20 > FLAG -1680 208 0 >=20 > FLAG -1680 704 0 >=20 > FLAG -1392 176 OUT1 >=20 > FLAG -1392 672 OUT2 >=20 > SYMBOL ind2 -2016 96 R0 >=20 > WINDOW 0 45 47 Left 2 >=20 > WINDOW 3 45 79 Left 2 >=20 > SYMATTR InstName L1 >=20 > SYMATTR Value 50 >=20 > SYMATTR Type ind >=20 > SYMATTR SpiceLine Rser=3D,1 >=20 > SYMBOL voltage -2144 112 R0 >=20 > WINDOW 3 24 104 Invisible 2 >=20 > WINDOW 123 0 0 Left 2 >=20 > WINDOW 39 0 0 Left 2 >=20 > SYMATTR Value SINE(0 170 60) >=20 > SYMATTR InstName V2 >=20 > SYMBOL ind2 -1792 208 R180 >=20 > WINDOW 0 42 73 Left 2 >=20 > WINDOW 3 48 42 Left 2 >=20 > SYMATTR InstName L2 >=20 > SYMATTR Value .5 >=20 > SYMATTR Type ind >=20 > SYMBOL res -1472 112 R90 >=20 > WINDOW 0 0 56 VBottom 2 >=20 > WINDOW 3 32 56 VTop 2 >=20 > SYMATTR InstName RL1 >=20 > SYMATTR Value 16 >=20 > SYMBOL diode -1456 16 R0 >=20 > WINDOW 0 -38 34 Left 2 >=20 > WINDOW 3 -98 -1 Left 2 >=20 > SYMATTR InstName D3 >=20 > SYMATTR Value MURS320 >=20 > SYMBOL diode -1648 272 R0 >=20 > WINDOW 0 -38 34 Left 2 >=20 > WINDOW 3 -96 72 Left 2 >=20 > SYMATTR InstName D2 >=20 > SYMATTR Value MURS320 >=20 > SYMBOL diode -1616 80 R180 >=20 > WINDOW 0 42 34 Left 2 >=20 > WINDOW 3 24 69 Left 2 >=20 > SYMATTR InstName D1 >=20 > SYMATTR Value MURS320 >=20 > SYMBOL diode -1424 336 R180 >=20 > WINDOW 0 42 32 Left 2 >=20 > WINDOW 3 24 0 Left 2 >=20 > SYMATTR InstName D4 >=20 > SYMATTR Value MURS320 >=20 > SYMBOL ind2 -1792 704 R180 >=20 > WINDOW 0 40 67 Left 2 >=20 > WINDOW 3 45 40 Left 2 >=20 > SYMATTR InstName L3 >=20 > SYMATTR Value .5 >=20 > SYMATTR Type ind >=20 > SYMBOL res -1472 608 R90 >=20 > WINDOW 0 0 56 VBottom 2 >=20 > WINDOW 3 32 56 VTop 2 >=20 > SYMATTR InstName RL2 >=20 > SYMATTR Value 16 >=20 > SYMBOL diode -1456 512 R0 >=20 > WINDOW 0 -38 34 Left 2 >=20 > WINDOW 3 -98 -1 Left 2 >=20 > SYMATTR InstName D7 >=20 > SYMATTR Value MURS320 >=20 > SYMBOL diode -1648 768 R0 >=20 > WINDOW 0 -38 34 Left 2 >=20 > WINDOW 3 -96 72 Left 2 >=20 > SYMATTR InstName D6 >=20 > SYMATTR Value MURS320 >=20 > SYMBOL diode -1616 576 R180 >=20 > WINDOW 0 42 34 Left 2 >=20 > WINDOW 3 24 69 Left 2 >=20 > SYMATTR InstName D5 >=20 > SYMATTR Value MURS320 >=20 > SYMBOL diode -1424 832 R180 >=20 > WINDOW 0 42 32 Left 2 >=20 > WINDOW 3 24 0 Left 2 >=20 > SYMATTR InstName D8 >=20 > SYMATTR Value MURS320 >=20 > SYMBOL res -1840 352 R90 >=20 > WINDOW 0 0 56 VBottom 2 >=20 > WINDOW 3 32 56 VTop 2 >=20 > SYMATTR InstName R2 >=20 > SYMATTR Value 1G >=20 > SYMBOL res -1840 848 R90 >=20 > WINDOW 0 0 56 VBottom 2 >=20 > WINDOW 3 32 56 VTop 2 >=20 > SYMATTR InstName R3 >=20 > SYMATTR Value 1G >=20 > SYMBOL polcap -1504 208 R90 >=20 > WINDOW 0 0 32 VBottom 2 >=20 > WINDOW 3 32 32 VTop 2 >=20 > SYMATTR InstName C1 >=20 > SYMATTR Value 10000=B5 >=20 > SYMBOL polcap -1504 704 R90 >=20 > WINDOW 0 0 32 VBottom 2 >=20 > WINDOW 3 32 32 VTop 2 >=20 > SYMATTR InstName C2 >=20 > SYMATTR Value 10000=B5 >=20 > TEXT -2136 400 Left 2 !.tran 1 >=20 > TEXT -1984 80 Left 2 !K1 L1 L2 L3 1 >=20 > TEXT -2160 432 Left 2 ;JOHN FIELDS >=20 > TEXT -2160 464 Left 2 ;04 OCT 2013
Thanks for the LTSpice file, but I use=20 Ngspice, which like HSpice, uses text file input.
On Monday, November 4, 2013 11:04:22 AM UTC-5, Tim Wescott wrote:
> On Sun, 03 Nov 2013 20:21:46 -0800, dakupoto wrote: > > > > > Could some electronics guru please shed some light on the following. The > > > standard topology for a linear regulated power supply is basically as > > > follows: > > > isolation step-down transformer > > > | > > > v > > > rectifier(bridge or 2 - diode) > > > | > > > v > > > capacitor ripple filter bank > > > | > > > v > > > voltage regulator > > > | > > > v > > > capacitor ripple filter bank > > > | > > > V > > > Let us suppose that the transformer is a step-down 9 - 0 - 9 1 Amp > > > output device. > > > > > > Now suppose I want to get two 1 Amp outputs by having a 9 - 0 -9 2 Amp > > > transformer and splitting its output equally with resistors as : > > > isolation step-down transformer > > > | | > > > v v > > > resistor resistor > > > | | > > > V V > > > rectifier etc., rectifier etc., > > > Is this a valid topology ? Or should there be two 9 - 0 - 9 1 Amp > > > isolation transformers connected to the common Ac wall input, and then > > > parallel topology as above, without the resistors. > > > Any thoughts, suggestions would be appreciated. > > > Thanks in advance. > > > > The resistors are unnecessary. > > > > If you don't need it to be isolated, just make a 2A supply and hook the > > loads up in parallel. > > > > I think you fail to understand the distinction between the current > > _rating_ on a supply and the current drawn by a load at a particular > > voltage, but I'm not sure. > > > > -- > > Tim Wescott > > Control system and signal processing consulting > > www.wescottdesign.com
Thanks. I am aware of the power rating, versus the actual current drawn by the load. Thanks to each of you for your feedback.
On Mon, 4 Nov 2013 20:13:22 -0800 (PST), dakupoto@gmail.com wrote:

>Thanks for the LTSpice file, but I use >Ngspice, which like HSpice, uses text >file input.
--- Sorry to have disturbed your turpor.
On Mon, 4 Nov 2013 20:13:22 -0800 (PST), dakupoto@gmail.com wrote:

>On Monday, November 4, 2013 10:17:57 AM UTC-5, John Fields wrote: >> On Mon, 04 Nov 2013 05:55:27 -0600, John Fields >> >> <jfields@austininstruments.com> wrote: >> >> >> >> >> >> >--- >> >> >If you have a 2A transformer and 1A loads and you need to isolate >> >> >the loads, a more sensible arrangement would be to run a separate >> >> >FWB supply off of each secondary since 1A transformers will overheat >> >> >if you're using capacitor input filters. >> >> >--- >> >> >> >> Version 4 >> >> SHEET 1 880 920 >>
[snip]
>> >> TEXT -1984 80 Left 2 !K1 L1 L2 L3 1 >> >> TEXT -2160 432 Left 2 ;JOHN FIELDS >> >> TEXT -2160 464 Left 2 ;04 OCT 2013 > >Thanks for the LTSpice file, but I use >Ngspice, which like HSpice, uses text >file input.
Suggestions: (1) Lose google and the added white-space (2) Get LTspice, it's free (3) If you must use NGspice, export the netlist from LTspice into NGspice. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.