Physics Help Forum Looking for a machine

 Electricity and Magnetism Electricity and Magnetism Physics Help Forum

 Oct 2nd 2017, 12:13 AM #1 Junior Member   Join Date: Oct 2017 Posts: 3 Looking for a machine Hey :-) What machine/equipment can you change the ,electrical charges output, the voltages output and frequencies output? all at once Thanks
 Oct 2nd 2017, 01:19 AM #2 Senior Member   Join Date: Apr 2015 Location: Somerset, England Posts: 613 For voltage output equipment the current is determined by the load not by the machine. (Ohm's Law) So it is impossible to control both the voltage and current simultaneously. So I guess you could modify a wobbulator or another type of swept frequency generator top simultaneously sweep either current or voltage output simultaneously. Why do you want this? topsquark likes this.
 Oct 2nd 2017, 07:48 AM #3 Junior Member   Join Date: Oct 2017 Posts: 3 okay thanks - its for a experiment Im trying to figure out what machine this man is using by reading the text: "And he experimented with putting a variety of different electrical charges, different voltages, frequencies, in different combinations"
Oct 2nd 2017, 08:36 AM   #4
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 Originally Posted by stenberg98 okay thanks - its for a experiment Im trying to figure out what machine this man is using by reading the text: "And he experimented with putting a variety of different electrical charges, different voltages, frequencies, in different combinations"

You seem to be indicating some equipment that you can set the parameters you describe to various different values.

A standard signal generator would allow you to set different frequencies and standard signal generators have a variable level control that can set the voltage output like a volume control on audio equipment does.

You would then set different frequencies one at a time and you could observe the effect of different voltage levels at each individual frequency.

Since nearly all lab equipment provides a voltage output you would have to arrange to vary the load resistance to vary the current.

Charge is the wrong term to use.

More specialist signal generators will vary either the voltage or frequency for you automatically the variable frequency one is called a sweep generator or wobbulator and the varibale voltage one a ramp generator.

I say again you cannot control both the voltage and the current at the same time it is either one or the other.

The only lab equipment I can think of which offers current control you can set to values would be semiconductor testers where you can choose a set current and then measure the voltage.
Usually these also allow you to set the voltage and then measure the current.
Some can also do this at several frequencies - switchable rather than continuously variable.

 Oct 3rd 2017, 05:05 AM #5 Senior Member     Join Date: Jun 2016 Location: England Posts: 264 A fuller description of the experiment being referred to might clarify the question. The use of the term "charge" might imply static electricity, in which case "voltage" and "charge" are so closely connected as to be practically synonyms. Where frequency might come into such a scenario is less clear. The linking of "frequency" and "charge" might perhaps relate to the performance of capacitors, (possibly resonant circuits)? The options are wide open, and the precise interpretation of the terms used depends on the particular type of process being measured. __________________ ~\o/~
Oct 3rd 2017, 05:27 AM   #6
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 Originally Posted by Woody A fuller description of the experiment being referred to might clarify the question. The use of the term "charge" might imply static electricity, in which case "voltage" and "charge" are so closely connected as to be practically synonyms. Where frequency might come into such a scenario is less clear. The linking of "frequency" and "charge" might perhaps relate to the performance of capacitors, (possibly resonant circuits)? The options are wide open, and the precise interpretation of the terms used depends on the particular type of process being measured.
And just how does static electricity have frequency, except a notional zero one?

Oct 3rd 2017, 09:24 AM   #7
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 Originally Posted by studiot And just how does static electricity have frequency, except a notional zero one?
Exactly;
The original post seems to include a set of mutually incompatible terms.
Either stenberg98 has misunderstood the original text:
 "And he experimented with putting a variety of different electrical charges, different voltages, frequencies, in different combinations"
or I am misunderstanding his post (or both)

Some additional context on the quote might clarify the issue.
__________________
~\o/~

Last edited by Woody; Oct 3rd 2017 at 10:00 AM.

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