hi,

I have two 12v batteries which I am hooking up in parallel using a
mechanical switch (via the ground).
I am attempting to swap the mechanical switch for a mosfet so I can
control them from a distance.
I tried to model in pspice but this is harder then I imagine. I tried
it experimentally, but when I hook up a iRFz44 , the batteries stays
in parallel no matter the voltage in the base. anyone has an idea to
overcome this.

B

lerameur wrote:

> hi,
> 
> I have two 12v batteries which I am hooking up in parallel using a
> mechanical switch (via the ground).
> I am attempting to swap the mechanical switch for a mosfet so I can
> control them from a distance.
> I tried to model in pspice but this is harder then I imagine. I tried
> it experimentally, but when I hook up a iRFz44 , the batteries stays
> in parallel no matter the voltage in the base. anyone has an idea to
> overcome this.
> 
> B
  If you can't show the circuit then please try to describe its 
connections..
   My guess is that you're using it incorrectly!.

   This Mosfet has a body diode in it, which means if you apply
  + voltage on the source, it'll be there at the drain. And the
Gate is a voltage control device not a current device as you are using
in terms of (BASE). You should at least have a pull down R to ground so
that you keep the gate discharged!. IT's a very high Z input which can
maintain a charge. You also can damage it.

   Since this component is a N channel device, you need to pull the
(-) terminal of the battery to common via the Drain connection of
the NMos and the Source goes to common..

    The Gate will be switched on via what ever voltage needed.
  I didn't look at all of the spec's

http://webpages.charter.net/jamie_5";

On Aug 16, 7:34 pm, Jamie
<jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
> lerameur wrote:
> > hi,
>
> > I have two 12v batteries which I am hooking up in parallel using a
> > mechanical switch (via the ground).
> > I am attempting to swap the mechanical switch for a mosfet so I can
> > control them from a distance.
> > I tried to model in pspice but this is harder then I imagine. I tried
> > it experimentally, but when I hook up a iRFz44 , the batteries stays
> > in parallel no matter the voltage in the base. anyone has an idea to
> > overcome this.
>
> > B
>
>   If you can't show the circuit then please try to describe its
> connections..
>    My guess is that you're using it incorrectly!.
>
>    This Mosfet has a body diode in it, which means if you apply
>   + voltage on the source, it'll be there at the drain. And the
> Gate is a voltage control device not a current device as you are using
> in terms of (BASE). You should at least have a pull down R to ground so
> that you keep the gate discharged!. IT's a very high Z input which can
> maintain a charge. You also can damage it.
>
>    Since this component is a N channel device, you need to pull the
> (-) terminal of the battery to common via the Drain connection of
> the NMos and the Source goes to common..
>
>     The Gate will be switched on via what ever voltage needed.
>   I didn't look at all of the spec's
>
> http://webpages.charter.net/jamie_5";

the circuit is really simple.
connection the ground of two batteries, the positives are not attached
to anything.
yes I could use an alligator clip and hook up the two grounds
together. But I would like to use a semiconductor. I would need some
sort of mosfet but when the gate is activated, it can let current flow
in both direction, is there anything on the market that can do this?

B

On Aug 16, 9:03 pm, lerameur <leram...@yahoo.com> wrote:
> On Aug 16, 7:34 pm, Jamie
>
>
>
> <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
> > lerameur wrote:
> > > hi,
>
> > > I have two 12v batteries which I am hooking up in parallel using a
> > > mechanical switch (via the ground).
> > > I am attempting to swap the mechanical switch for a mosfet so I can
> > > control them from a distance.
> > > I tried to model in pspice but this is harder then I imagine. I tried
> > > it experimentally, but when I hook up a iRFz44 , the batteries stays
> > > in parallel no matter the voltage in the base. anyone has an idea to
> > > overcome this.
>
> > > B
>
> >   If you can't show the circuit then please try to describe its
> > connections..
> >    My guess is that you're using it incorrectly!.
>
> >    This Mosfet has a body diode in it, which means if you apply
> >   + voltage on the source, it'll be there at the drain. And the
> > Gate is a voltage control device not a current device as you are using
> > in terms of (BASE). You should at least have a pull down R to ground so
> > that you keep the gate discharged!. IT's a very high Z input which can
> > maintain a charge. You also can damage it.
>
> >    Since this component is a N channel device, you need to pull the
> > (-) terminal of the battery to common via the Drain connection of
> > the NMos and the Source goes to common..
>
> >     The Gate will be switched on via what ever voltage needed.
> >   I didn't look at all of the spec's
>
> >http://webpages.charter.net/jamie_5";
>
> the circuit is really simple.
> connection the ground of two batteries, the positives are not attached
> to anything.
> yes I could use an alligator clip and hook up the two grounds
> together. But I would like to use a semiconductor. I would need some
> sort of mosfet but when the gate is activated, it can let current flow
> in both direction, is there anything on the market that can do this?
>
> B

I think it is called a UJT, just need to find one in pspice...

B

lerameur wrote:

> On Aug 16, 7:34 pm, Jamie
> <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
> 
>>lerameur wrote:
>>
>>>hi,
>>
>>>I have two 12v batteries which I am hooking up in parallel using a
>>>mechanical switch (via the ground).
>>>I am attempting to swap the mechanical switch for a mosfet so I can
>>>control them from a distance.
>>>I tried to model in pspice but this is harder then I imagine. I tried
>>>it experimentally, but when I hook up a iRFz44 , the batteries stays
>>>in parallel no matter the voltage in the base. anyone has an idea to
>>>overcome this.
>>
>>>B
>>
>>  If you can't show the circuit then please try to describe its
>>connections..
>>   My guess is that you're using it incorrectly!.
>>
>>   This Mosfet has a body diode in it, which means if you apply
>>  + voltage on the source, it'll be there at the drain. And the
>>Gate is a voltage control device not a current device as you are using
>>in terms of (BASE). You should at least have a pull down R to ground so
>>that you keep the gate discharged!. IT's a very high Z input which can
>>maintain a charge. You also can damage it.
>>
>>   Since this component is a N channel device, you need to pull the
>>(-) terminal of the battery to common via the Drain connection of
>>the NMos and the Source goes to common..
>>
>>    The Gate will be switched on via what ever voltage needed.
>>  I didn't look at all of the spec's
>>
>>http://webpages.charter.net/jamie_5";
> 
> 
> the circuit is really simple.
> connection the ground of two batteries, the positives are not attached
> to anything.
> yes I could use an alligator clip and hook up the two grounds
> together. But I would like to use a semiconductor. I would need some
> sort of mosfet but when the gate is activated, it can let current flow
> in both direction, is there anything on the market that can do this?
> 
> B
Are you saying you want to put these batteries in series ?

   I think at this point you maybe better off using a relay..


http://webpages.charter.net/jamie_5";

On Aug 16, 10:34 pm, Jamie
<jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
> lerameur wrote:
> > On Aug 16, 7:34 pm, Jamie
> > <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
>
> >>lerameur wrote:
>
> >>>hi,
>
> >>>I have two 12v batteries which I am hooking up in parallel using a
> >>>mechanical switch (via the ground).
> >>>I am attempting to swap the mechanical switch for a mosfet so I can
> >>>control them from a distance.
> >>>I tried to model in pspice but this is harder then I imagine. I tried
> >>>it experimentally, but when I hook up a iRFz44 , the batteries stays
> >>>in parallel no matter the voltage in the base. anyone has an idea to
> >>>overcome this.
>
> >>>B
>
> >>  If you can't show the circuit then please try to describe its
> >>connections..
> >>   My guess is that you're using it incorrectly!.
>
> >>   This Mosfet has a body diode in it, which means if you apply
> >>  + voltage on the source, it'll be there at the drain. And the
> >>Gate is a voltage control device not a current device as you are using
> >>in terms of (BASE). You should at least have a pull down R to ground so
> >>that you keep the gate discharged!. IT's a very high Z input which can
> >>maintain a charge. You also can damage it.
>
> >>   Since this component is a N channel device, you need to pull the
> >>(-) terminal of the battery to common via the Drain connection of
> >>the NMos and the Source goes to common..
>
> >>    The Gate will be switched on via what ever voltage needed.
> >>  I didn't look at all of the spec's
>
> >>http://webpages.charter.net/jamie_5";
>
> > the circuit is really simple.
> > connection the ground of two batteries, the positives are not attached
> > to anything.
> > yes I could use an alligator clip and hook up the two grounds
> > together. But I would like to use a semiconductor. I would need some
> > sort of mosfet but when the gate is activated, it can let current flow
> > in both direction, is there anything on the market that can do this?
>
> > B
>
> Are you saying you want to put these batteries in series ?
>
>    I think at this point you maybe better off using a relay..
>
> http://webpages.charter.net/jamie_5";

two grounds together, that would be parallel, But the UJT is taking
too much current just to enable it. The problem is that when I put a
MOsfet  with source on one grounds and the drain on the other ground,
the batteries are in parallel. no matter what the gate voltage is...

B

On Aug 17, 5:34=A0am, Jamie
<jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
> lerameur wrote:
> > On Aug 16, 7:34 pm, Jamie
> > <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
>
> >>lerameur wrote:
>
> >>>hi,
>
> >>>I have two 12v batteries which I am hooking up in parallel using a
> >>>mechanical switch (via the ground).
> >>>I am attempting to swap the mechanical switch for a mosfet so I can
> >>>control them from a distance.
> >>>I tried to model in pspice but this is harder then I imagine. I tried
> >>>it experimentally, but when I hook up a iRFz44 , the batteries stays
> >>>in parallel no matter the voltage in the base. anyone has an idea to
> >>>overcome this.
>
> >>>B
>
> >> =A0If you can't show the circuit then please try to describe its
> >>connections..
> >> =A0 My guess is that you're using it incorrectly!.
>
> >> =A0 This Mosfet has a body diode in it, which means if you apply
> >> =A0+ voltage on the source, it'll be there at the drain. And the
> >>Gate is a voltage control device not a current device as you are using
> >>in terms of (BASE). You should at least have a pull down R to ground so
> >>that you keep the gate discharged!. IT's a very high Z input which can
> >>maintain a charge. You also can damage it.
>
> >> =A0 Since this component is a N channel device, you need to pull the
> >>(-) terminal of the battery to common via the Drain connection of
> >>the NMos and the Source goes to common..
>
> >> =A0 =A0The Gate will be switched on via what ever voltage needed.
> >> =A0I didn't look at all of the spec's
>
> >>http://webpages.charter.net/jamie_5";
>
> > the circuit is really simple.
> > connection the ground of two batteries, the positives are not attached
> > to anything.
> > yes I could use an alligator clip and hook up the two grounds
> > together. But I would like to use a semiconductor. I would need some
> > sort of mosfet but when the gate is activated, it can let current flow
> > in both direction, is there anything on the market that can do this?
>
> > B
>
> Are you saying you want to put these batteries in series ?
>
> =A0 =A0I think at this point you maybe better off using a relay..
>
> http://webpages.charter.net/jamie_5";

Remember Occam's razor.

Don't use a transistor when a switch will do; don't use an IC when a
transistor will do........

On 2008-08-17, lerameur <l...@yahoo.com> wrote:
> On Aug 16, 7:34 pm, Jamie
><jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
>> lerameur wrote:
>> > hi,
>>
>> > I have two 12v batteries which I am hooking up in parallel using a
>> > mechanical switch (via the ground).
>> > I am attempting to swap the mechanical switch for a mosfet so I can
>> > control them from a distance.
>> > I tried to model in pspice but this is harder then I imagine. I tried
>> > it experimentally, but when I hook up a iRFz44 , the batteries stays
>> > in parallel no matter the voltage in the base. anyone has an idea to
>> > overcome this.
>>
>
> the circuit is really simple.
> connection the ground of two batteries, the positives are not attached
> to anything.

Batteries connected like that will do nothing, more details would help.

> yes I could use an alligator clip and hook up the two grounds
> together. But I would like to use a semiconductor. I would need some
> sort of mosfet but when the gate is activated, it can let current flow
> in both direction, is there anything on the market that can do this?

MOSFETs will do that they just have that annoying body diode that
makes them always conduct (like a diode) in the backwards direction.

you may be able to escape this problem by connecting two back-to
back.

connect the gates together and the drains, then connect the sources
to the batteries and the gates to your control signal.

Bye.
   Jasen

"lerameur"

**  =  primate relative of the lemur


> But the UJT is taking...


** Huh  ?????????

UJT   =   what ?

Uni - junction transistor  ???

The term you want is " BJT "    -  fuckwit.





.....   Phil

On Sun, 17 Aug 2008 03:36:20 -0700 (PDT), lerameur
<l...@yahoo.com> wrote:

>On Aug 16, 10:34 pm, Jamie
><jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
>> lerameur wrote:
>> > On Aug 16, 7:34 pm, Jamie
>> > <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
>>
>> >>lerameur wrote:
>>
>> >>>hi,
>>
>> >>>I have two 12v batteries which I am hooking up in parallel using a
>> >>>mechanical switch (via the ground).
>> >>>I am attempting to swap the mechanical switch for a mosfet so I can
>> >>>control them from a distance.
>> >>>I tried to model in pspice but this is harder then I imagine. I tried
>> >>>it experimentally, but when I hook up a iRFz44 , the batteries stays
>> >>>in parallel no matter the voltage in the base. anyone has an idea to
>> >>>overcome this.
>>
>> >>>B
>>
>> >>  If you can't show the circuit then please try to describe its
>> >>connections..
>> >>   My guess is that you're using it incorrectly!.
>>
>> >>   This Mosfet has a body diode in it, which means if you apply
>> >>  + voltage on the source, it'll be there at the drain. And the
>> >>Gate is a voltage control device not a current device as you are using
>> >>in terms of (BASE). You should at least have a pull down R to ground so
>> >>that you keep the gate discharged!. IT's a very high Z input which can
>> >>maintain a charge. You also can damage it.
>>
>> >>   Since this component is a N channel device, you need to pull the
>> >>(-) terminal of the battery to common via the Drain connection of
>> >>the NMos and the Source goes to common..
>>
>> >>    The Gate will be switched on via what ever voltage needed.
>> >>  I didn't look at all of the spec's
>>
>> >>http://webpages.charter.net/jamie_5";
>>
>> > the circuit is really simple.
>> > connection the ground of two batteries, the positives are not attached
>> > to anything.
>> > yes I could use an alligator clip and hook up the two grounds
>> > together. But I would like to use a semiconductor. I would need some
>> > sort of mosfet but when the gate is activated, it can let current flow
>> > in both direction, is there anything on the market that can do this?
>>
>> > B
>>
>> Are you saying you want to put these batteries in series ?
>>
>>    I think at this point you maybe better off using a relay..
>>
>> http://webpages.charter.net/jamie_5";
>
>two grounds together, that would be parallel, But the UJT is taking
>too much current just to enable it. The problem is that when I put a
>MOsfet  with source on one grounds and the drain on the other ground,
>the batteries are in parallel. no matter what the gate voltage is...

---
Assuming you want to drive some sort of load, this should do it:

Version 4
SHEET 1 1268 944
WIRE -32 48 -352 48
WIRE 144 48 -32 48
WIRE 320 48 144 48
WIRE -352 112 -352 48
WIRE -32 128 -32 48
WIRE 144 128 144 48
WIRE -528 256 -592 256
WIRE -400 256 -528 256
WIRE -192 256 -400 256
WIRE -592 288 -592 256
WIRE 320 288 320 48
WIRE -528 336 -528 256
WIRE -352 336 -352 192
WIRE -192 336 -192 256
WIRE -400 352 -400 256
WIRE -32 448 -32 208
WIRE 144 448 144 208
WIRE -528 496 -528 416
WIRE -400 496 -400 400
WIRE -400 496 -528 496
WIRE -352 496 -352 416
WIRE -192 496 -192 416
WIRE -192 496 -352 496
WIRE -128 496 -192 496
WIRE -96 496 -128 496
WIRE 240 496 208 496
WIRE -128 592 -128 496
WIRE 240 592 240 496
WIRE 240 592 -128 592
WIRE -32 656 -32 544
WIRE 144 656 144 544
WIRE 144 656 -32 656
WIRE 320 656 320 368
WIRE 320 656 144 656
FLAG -592 288 0
SYMBOL voltage -528 432 R180
WINDOW 0 -53 5 Left 0
WINDOW 3 -242 110 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 1 0 1E-6 1E-6 1 2)
SYMBOL sw -352 320 R0
WINDOW 0 32 15 Left 0
WINDOW 3 32 44 Left 0
SYMATTR InstName S2
SYMBOL npn -96 544 M180
SYMATTR InstName Q1
SYMATTR Value 2N2222
SYMBOL voltage -32 112 R0
WINDOW 0 -53 5 Left 0
WINDOW 3 -242 110 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL res 304 272 R0
SYMATTR InstName R2
SYMATTR Value 24
SYMBOL res -208 320 R0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL res -368 96 R0
SYMATTR InstName R3
SYMATTR Value 1k
SYMBOL voltage 144 112 R0
WINDOW 0 -53 5 Left 0
WINDOW 3 -242 110 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value 12
SYMBOL npn 208 544 R180
SYMATTR InstName Q2
SYMATTR Value 2N2222
TEXT -720 528 Left 0 !.model SW SW(Ron=.01 Roff=10Meg Vt=0.5Vh=0)
TEXT -712 488 Left 0 !.tran 0 10 0


But what are you trying to do?

JF