polarity inversion switch

[[email protected]]

Hello, i need some help with a little project im working on. I need
to make a circuit board that allows me to invert polarity on a
circuit. I want to make anything i hook up to the circuitboard be
able to switch from positive to negitave multiple times a second. like
about 100 times a second or so. Like from -6v to 8v, then from 8v to
-4v. I want to be able to control how much voltage i can put. Like
if the circuit switched polarity 100 times a second i want to be able
to program the circuit to put out the voltages i desire. Ive heard
that this project is impossible, but maybe someone can help me. PLZ
help

 

[[email protected]]

Hello, i need some help with a little project im working on. I need
to make a circuit board that allows me to invert polarity on a
circuit. I want to make anything i hook up to the circuitboard be
able to switch from positive to negitave multiple times a second. like
about 100 times a second or so. Like from -6v to 8v, then from 8v to
-4v. I want to be able to control how much voltage i can put. Like
if the circuit switched polarity 100 times a second i want to be able
to program the circuit to put out the voltages i desire. Ive heard
that this project is impossible, but maybe someone can help me. PLZ
help

I forgot to say that i want to hook this circuit to a battery, not an
outlet. So i guess that is dc maybe? Im not too much on electronics

 

[Eeyore]

Hello, i need some help with a little project im working on. I need
to make a circuit board that allows me to invert polarity on a
circuit. I want to make anything i hook up to the circuitboard be
able to switch from positive to negitave multiple times a second. like
about 100 times a second or so. Like from -6v to 8v, then from 8v to
-4v. I want to be able to control how much voltage i can put. Like
if the circuit switched polarity 100 times a second i want to be able
to program the circuit to put out the voltages i desire. Ive heard
that this project is impossible, but maybe someone can help me. PLZ
help

What is the signal you want to invert ? What is the voltage, current, impedance,
frequency/repetition rate, waveform shape, rise/fall time etc ?

Graham

 

[whit3rd]

.... I need
to make a circuit board that allows me to invert polarity on a
circuit. I want to make anything i hook up to the circuitboard be
able to switch from positive to negitave multiple times a second.

Depending on what the 'anything I hook up' is, the best answer could
be
(a) a DPDT switch
(b) an XOR gate
(c) a diode mixer that accepts DC on the LO port
(d) a transconductance multiplier
(e) a center-tapped transformer with a relay or analog multiplexer

and if we reading sci.electronics.design put our minds to it, that
could stretch
to (m) pretty easily.

 

[[email protected]]

Depending on what the 'anything I hook up' is, the best answer could
be
(a) a DPDT switch
(b) an XOR gate
(c) a diode mixer that accepts DC on the LO port
(d) a transconductance multiplier
(e) a center-tapped transformer with a relay or analog multiplexer

and if we reading sci.electronics.design put our minds to it, that
could stretch
to (m) pretty easily.

i have 4 nine volt batterys. I made electromagnets. I want to be able
to flip voltage from 9 volts to -9 volts. it doesnt matter the amps. I
need the voltage to jump from 9 volts to off to -9 volts. to off to 9
volts to off to -9 volts.( if that makes any sense) I want to have
something i guess like a potentiometer. but more like a button, or (a
gas pedal for example). the further i turn it the more volts it will
push and when i turn it the opposite way the volts will decrease. and
i need it to be set like this: at 1 volt i need to switch from 1 volt
to off to -1 volt10 times a second. and at 9 volts i need to switch
from 9 volts to off to -9 volts 90 times a second. I need to hook the
chip up to two batteries at one time. as you can see im not too good
at electronics but i hope someone can help me. I might need to give
somemore information. im not sure tho.

 

[whit3rd]

i have 4 nine volt batterys. I made electromagnets. I want to be able
to flip voltage from 9 volts to -9 volts.

OK, that's enough to go on. A 9V battery might have 5 ohms output
resistance, so toggle switches, relays, and MOSFET bridges are
possible
elements to perform the function.

Switching an electromagnet, however, is VERY stressful;
switching the ignition coil in a car both generates the 40,000 V
that goes to the spark plug, and wears out a set of 'points' on
a regular schedule (old cars used points). The magnetization doesn't
switch immediately, by the way. That 5 ohms resistance in
the battery combines with the resistance and inductance of the
electromagnet to make a turnon delay.

This kind of switching is built in to some switchmode power supply
control chips; you describe a control voltage that changes the switch
frequency, and that is similar to PWM full bridge control function.
There are single-chip items to drive motors that might fit your need
exactly, see
<http://www.allegromicro.com/en/Products/Part_Numbers/3966/>
for a typical such item (it has two sections; you might only need
one).
Web searches for "PWM" and "full bridge" will get you lots of
suggestions.

Alas, by the time you get any such solution up and running, you WILL
know
a lot about electronics. Thirty years ago, I'd have suggested 'get a
vibrator', there were vacuum-tube era canned solutions to this problem
in all the old auto radios.