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How to limit DC current without affecting Voltage? Answered

I would like to be able to choke current example 12-20amps from the 40amp peak to peak keeping voltage level to rise when the current begins to fall again as stabling after a huge load peak. This will preserve energy consumption on my circuit.

Things ive researched

Transformer choke
Current limit thorough chips
add a pwm and control (expensive and time consuming)

6 Replies

ArturoC6 (author)2015-10-10

Well i have a motor that pulls a constant amperage and runs at 12v. The motor goes up and down in rpm dependent on load. Since a drop in rpm will not hurt the system. Id like to have a way to control current to not overheat the dc motors. Does having a h bridge with pwm help control heat i was thinking with a arduino.

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steveastrouk (author)ArturoC62015-10-10

You're trying to beat physics, and you can't. A DC motor draws a variable current depending on its load, to draw that current, the RPM changes.

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rickharris (author)steveastrouk2015-10-11

+1 Fixing the current will just cause the motor to drop more RPM under load - or to look at it another way it will limit the output of the motor.

As I said originally you need to be MUCH more specific in your project requirements to allow us to asses what you can or an not do.

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Downunder35m (author)2015-10-10

I think you did not understand the basics of electrics.
And I don't even try to explain things as there is not enough from your end to go with.

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iceng (author)2015-10-10

It seems you do not have experience with DC power supplies.

If you have a [stiff = low impedance] DC power supply then it makes no difference if the current is full-flow, half-flow or not-flowing and the voltage will be constant = the same.

To adjust the current flow you will need a power mosfet and the electronics to control it. Weather you go analog or PWM depends on over 3 semesters of education and the load requirements you have not even mentioned.

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rickharris (author)2015-10-10

Yet again we need to know a lot more about what your trying to achieve.


will give you a constant current.

In general a circuit will draw the current it need to operate - or as much as it can depending on the type of circuit.

Power is a product of current and voltage - I x V=W

For a given voltage you will use a given wattage if the current if fixed. however your circuit may not operate as you think if you limit the current. (depends on what it is)

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