As you all probably know an electrical capacitor has the ability to be charged and hold this charge, when the circuit is closed the capacitor will then ‘dump’ all of its charge in a relatively short space of time. I was recently doing some DIY and being lazy using a cordless screwdriver which was great until it came to the last turn or so of the screw when the screwdriver would just grind to a frustrating stop, so my idea is to use a capacitor in conjunction with the motor, which would slowly draw current from the battery, and then as you are coming to the last turn or so, press a button which causes the capacitor to ‘dump’ its charge on the motor giving it that extra bit of power it needs to drive the screw right the way in. I know anybody who knows their components is then going to comment on the size of capacitor needed for such a job, after all a one farad capacitor is about the size of a can of tuna, depending on the voltage rating. This would hold 1 amp second at 1 volt, as the motor in the screwdriver works on a higher voltage than this, (around 4.7 volts), a 1 farad capacitor should do the job. But if the battery of the screwdriver was changed from the primitive NiCd batteries to a NiMH, which would hold more charge, or even a Lithium Ion Battery to keep the weight down, there’s no reason why this shouldn’t be accomplished. After all within reason the length of the screwdriver isn’t all that important, as any woman will tell you, it’s all about girth.
-- STE_2020, May 26 2003

The problem you are describing, is one of torque, not available energy. Adding more electrical *omph*, will not be very effective. The low-speed/high torque power driver is well baked.
-- ato_de, May 27 2003


//As you all probably know// (your first words on this) This was the worst part of your idea. Actually not everyone does. I had to look up both the words capacitator (to store charge temporarily) and torque (rotating force) My best guess going in was the first had to do with amount of charge held since I spelt it wrong (capacitator) and I had a clue what the second might be (fairly accurate but had to read the 1st & 2nd definitions to compare and confirm).

What does this have to do with anything. It's not what you know that matters (no matter what a persons education they can't be knowledgable in depth &/or about all things) it's how you use it to extrapolate your knowledge into making a decision as to whether something you have little knowledge of makes sense. This lets a person not pander to so called authority and also to make decisions when no expert is available in everyday situations.

As such, my take on your idea, with a little help from ato_de's annotation, dictionary.com, a bit of time/effort and a general view is ... why not.

1)Why would 'lotsa' rotating force "not be very effective". 2) You did provide backup to your argument, and while in nice layperson's terms (thank you) ato_de's argument was ultimately too sparse and generic to convince me.

Finally, you can't argue with your last sentence :).
-- thecat, Jun 19 2003


Use an impact wrench.
-- supercat, Jun 19 2003



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