I have a circuit composed of Lm393 with 12v power supply. I can output two synchronous pulses: +12v and -12v I would like to put a coil between so I get a 24v difference. Taking the positive side and hooking it up to the coil and a mosfet after the coil. Can I use the -12v as my drain on the mosfet ? I dont want to blow anything up so thats why I am asking what would be best way to do this. I also heard that i needed to one mosfet for positive and one mosfet for negative side .... any ideas? thanks
to do this. I also heard that i needed to one mosfet for positive and one mosfet for negative side ....
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Not trying to be difficult, but what you're saying makes no sense at
all.
To me, anyway.
Can you post your circuit and a description of what you want without
delving into what you think is the way to get there, please?
way to do this. I also heard that i needed to one mosfet for positive and one mosfet for negative side ....
I'll explain a bit better:
I have two LM393 with a 12v power supply. One of the LM393 is outputting pulses at +12v and the other LM393 at -12V. I would like to pulse a motor with that 24v difference. Obviously I cannot drive the motor with the LM393. So I thought of pulsing n-channel mosfet to drive the motor. If I had only the positive side to take of I would connect the drain to the motor and source to ground. What is confusing me is that I have a virtual -12v ground. How do I drive a motor with the 24v difference (+12v to -12v) ?
If you want 24V, why not use a 24V power supply on the LM393?
The outputs are good for 6 mA (guaranteed) current, and are 'off' half the time, so you'll get less than a tenth watt for your motor (at 12V) . Will that be a problem?
An oscillator and coil, with tap, can make any voltage you'd like (the Ford model A got kilovolts from a 6V battery this way).
way to do this. I also heard that i needed to one mosfet for positive and one mosfet for negative side ....
motor and source to ground. What is confusing me is that I have a virtual -12v ground. How do I drive a motor with the 24v difference (+12v to -12v) ?
If you have a virtual ground to give you a -12 volts, then that means you have a 24v source to start with?
Turning on the fet is simple, use an R to your virtual ground to the gate, connect the source to the -12 supply leg. when the comparator is in the off set, meaning the open collector is not on, the gate common R will switch the FET on. This is because the source is sitting at a -12, which looks like +12V at the gate if the source was on the common, Of course you need the open collector to also be connected to the gate along with the virtual ground R.
THe motor can be connected to the Drain of the Mfet while the other pole is connected to the +12V. This will give you the 24 volts to the motor while splitting the rail via a v-ground for the rest of your circuit.
Basically you only need one comparator sitting on a split rail, when the output is off, the gate R to common will turn on the MFET.
of course this does not give you a bridge so if you are thinking about reversing the motor, then you need some more semi-conductors.
My take on his latest insanity is that he wants to drive a 24V DC motor using a 12V DC supply by feeding the motor with pulses of alternating polarity.
way to do this. I also heard that i needed to one mosfet for positive and one mosfet for negative side ....
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This is a text-only group, so attachments aren't allowed.
Arguably, the easiest way is to draw your schematic using LTspice and
then post the ASCII circuit list here by pasting it into your article.
Failing that, you could draw an ASCII schematic and post that, or you
could use one of the web-based image hosting sites.
You could also post an attachment to a binaries (alt.binaries.*) group
if you weren't posting from google groups and you had a decent
newsreader.
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