Experimental Low Voltage, Low Milliamperes Device

hp1729

Joined Nov 23, 2015
2,304
The various experiments used voltages between 2 and 6 volts and current between 2 and 6 milliamps. One experiment cited "2.4 milliamps at less than 3 volts." So adjustable voltage and amperage within the above specified ranges would be best if there was a way to insure accurate digital readouts during adjustments.

Thanks
Ah, accurate digital readouts? Now you are getting specific enough to design with.

ci139

Joined Jul 11, 2016
1,696
Hi, I am hoping to built a battery powered, wearable unit that precisely outputs a constant voltage over a selectable 1 to 6 volt range
◄ That part makes sense
and a constant amperage over a selectable 1 to 6 milliamp range. Does this already exist? If not, any suggestions would be appreciated. Thanks
◄ That part does not - as everybody is trying to explain you ??? /!\ putting milli-ampere range direct current through the living cells is most likely NOT fu n to experiment with /!\

srodnesky

Joined Aug 6, 2016
12
◄ That part makes sense
◄ That part does not - as everybody is trying to explain you ??? /!\ putting milli-ampere range direct current through the living cells is most likely NOT fu n to experiment with /!\
Thanks for trying to 'help,' but if you review earlier post you would realize that we are talking about a calculated skin resistance of only 1,000 Ohms where the human body as you go deeper can have a resistance of up to 100,000 Ohms which would virtually neutralize the effects of such low volt/amp combos.

Plus, you probably did not read where this device is to be used to replicate already successful experiments.

To save your time and mine, please don't consider contributing, if you have not gotten up to speed on the goals and parameters of the project.

Ah, accurate digital readouts? Now you are getting specific enough to design with.
That would be great!

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ci139

Joined Jul 11, 2016
1,696
Quick TEST - thumb to thumb - dry skin:
9V apx. 10µA = 0.01mA (milliamperes) = 0.00001A
18V apx. 20µA
26V varying from 24 to 36 µA (depending on precise spot and electrode pressure)
??? you are "driving off" by 3 orders of magnitude

dannyf

Joined Sep 13, 2015
2,197
So adjustable voltage and amperage within the above specified ranges would be best if there was a way to insure accurate digital readouts during adjustments.
You are probably not reading the papers right. It is likely that they are applying a voltage, or a current source, and measure the current or voltage across the DUT. You cannot apply a given voltage AND a current on an arbitrary DUT - that's just physics.

If you know that your DUT is safe within a set voltage range, I would get an adjustable voltage regulator to control the voltage and then measure the current at a given voltage. This is the simplest route and can be done with a minimum number of parts.

Alternatively, if you know your DUT is safe within a set current range, get an adjustable current source and measure the voltage across the DUT.

dannyf

Joined Sep 13, 2015
2,197
a calculated skin resistance of only 1,000 Ohms
1K sounds too low. Hundreds of it or more is more likely.

tcmtech

Joined Nov 4, 2013
2,867
I have no idea why you and papabravo feel you have the right and/or responsibility to attempt to discourage me from pursuing this experiment. Please don't waste your time or mine.

Maybe because you have given zero information relating to said research s purpose and findings so to us all of this comes off as nothing more than crap science research based on false logic and poor understandings being so far your requirements have not passed basic logical scrutiny regarding basic electrical physics laws.

So yes we do have the right to question other people's motives and reasonings when what they present does not add up with basic logical reasoning.

What makes you think you have the right to not be questioned about the purpose and validity of your endeavor??

If you want better answers you have to give better information otherwise crap in = crap out.

tcmtech

Joined Nov 4, 2013
2,867
but if you review earlier post you would realize that we are talking about a calculated skin resistance of only 1,000 Ohms where the human body as you go deeper can have a resistance of up to 100,000 Ohms which would virtually neutralize the effects of such low volt/amp combos.
It's the reverse of that.

Our skin, especially when dry, has a fairly high electrical resistance but our internal organs are far more conductive.

Your reasoning and logic is wrong and hence the reason your getting questioned by everybody participating in this thread.

Alec_t

Joined Sep 17, 2013
12,070
Is the reason that you are repeating earlier experiments because you doubt their validity?

srodnesky

Joined Aug 6, 2016
12
Ah, accurate digital readouts? Now you are getting specific enough to design with.
Hi hp1729,

I am eagerly awaiting the next revision of your design when you have time.

Frankly, I don't normally use Forums and am surprised by the amount of energy expended by members trying to 'protect' me from myself.

Please let me know if there is any more information that you personally need from me .

Thanks again for your kind help.

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hp1729

Joined Nov 23, 2015
2,304
Hi hp1729,

I am eagerly awaiting the next revision of your design when you have time.

Frankly, I don't normally use Forums and am surprised by the amount of energy expended by members trying to 'protect' me from myself.

Please let me know if there is any more information that you personally need from me .

Thanks again for your kind help.
Not much more to it than adding meters on the output. Those with more engineering than I have may be able to suggest something better. The next question really is building. Are you going to build? As far as meters go, 0 to 10 V and 0 to 10 mA of your choice. Analog or digital?

tcmtech

Joined Nov 4, 2013
2,867
Frankly, I don't normally use Forums and am surprised by the amount of energy expended by members trying to 'protect' me from myself.
Well, I for one am not trying to protect you from yourself. In fact, If you want to electrocute yourself I want to make sure you have all the correct facts on how to do it properly the first time and just partially cook yourself.

As far as hp1729 contribution, his circuit would work just fine for a fixed resistance load BUT being us humans and our skin are for lack of a better term dynamic variable electrolytic resistors it's nearly useless for your application given the precise specifications you have asked for.

So which is it you need? Precise 1 - 6 volt output regardless of load or precise 1 - 6 mA current regardless of load and by load I mean skin contact being as of so far no one here has been able to achieve a skin point to point resistance of a 1000 ohms?

BTW my wet hands on aluminum foil (large contact areas) tested at around 9,000 ohms or 9 times higher than your 1000 ohm estimate you are using for your reference which makes passing even 1 mA at 6 volts impossible thus invalidating your basic precision requirements.

Also given you stated,
For your information I am simply trying to replicate research that has been accomplished several times over the past 60 years. The papers in question state the volt and current settings used, but like most abstracts do not include detailed equipment composition.
Who's research and what were they trying to accomplish?

srodnesky

Joined Aug 6, 2016
12
Not much more to it than adding meters on the output. Those with more engineering than I have may be able to suggest something better. The next question really is building. Are you going to build? As far as meters go, 0 to 10 V and 0 to 10 mA of your choice. Analog or digital?
Digital Meters would be preferred. I'm not sure whether it would be cost effective to repurpose digital meters from inexpensive multimeters of which I have several.

I plan to develop a parts list to price out. This is a side project rather than well-funded research. However, since my last breadboard project is more that than 40 yrs in the rear view mirror, I might just bid it out.

If you have any additional feedback, I would appreciate it. If you send an email and/or phone number in your next post, we can relieve the trolls from their need for future post on the subject.

If you are not comfortable spending additional time with this project. I want to once again express my since appreciation for the time and effort you have invested in your several post.

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bertus

Joined Apr 5, 2008
21,364
Hello,

I have merged a lot of sequential posts.
You can use the edit button to add information to a post.

Bertus

hp1729

Joined Nov 23, 2015
2,304
Digital Meters would be preferred. I'm not sure whether it would be cost effective to repurpose digital meters from inexpensive multimeters of which I have several.

I plan to develop a parts list to price out. This is a side project rather than well-funded research. However, since my last breadboard project is more that than 40 yrs in the rear view mirror, I might just bid it out.

If you have any additional feedback, I would appreciate it. If you send an email and/or phone number in your next post, we can relieve the trolls from their need for future post on the subject.

If you are not comfortable spending additional time with this project. I want to once again express my since appreciation for the time and effort you have invested in your several post.
Yes, take the project to someone local. Point them to the forum if they want. Off hand I couldn't find meters that nicely fit your needs. Yes cheap DMM is a good idea.

hp1729

Joined Nov 23, 2015
2,304
Well, I for one am not trying to protect you from yourself. In fact, If you want to electrocute yourself I want to make sure you have all the correct facts on how to do it properly the first time and just partially cook yourself.

As far as hp1729 contribution, his circuit would work just fine for a fixed resistance load BUT being us humans and our skin are for lack of a better term dynamic variable electrolytic resistors it's nearly useless for your application given the precise specifications you have asked for.

So which is it you need? Precise 1 - 6 volt output regardless of load or precise 1 - 6 mA current regardless of load and by load I mean skin contact being as of so far no one here has been able to achieve a skin point to point resistance of a 1000 ohms?

BTW my wet hands on aluminum foil (large contact areas) tested at around 9,000 ohms or 9 times higher than your 1000 ohm estimate you are using for your reference which makes passing even 1 mA at 6 volts impossible thus invalidating your basic precision requirements.

Also given you stated,

Who's research and what were they trying to accomplish?
Perhaps he is looking at "under the skin" resistances. Blocking nerves to relieve pain, for instance. If that is the case he can buy last year's model TENS units forb $20 to$50. Newer models go for about \$800. Embedded (all under the skin) devices use induction rechargers and external programming by the user.

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#12

Joined Nov 30, 2010
18,222
Hi. I want a car that has constant velocity and constant acceleration, both at the same time.
To be specific, it must go 30 miles per hour at all times and accelerate at a rate of 1 MPH per second at all times.

Got it?

ci139

Joined Jul 11, 2016
1,696
Perhaps I am not using the terminology correctly. One can readily purchase an AC to DC power supply with the following characteristics: output voltages: 3, 4.5, 6, 7.5, 9, 12V DC, output current: 800mA (regulated) . . .
((i gues this thread goes lengthy . . . whatever ))
• You are correct for quality swithed supplies that - as expected - specify that the Max. Current Draw AT specified Output Voltage
• You are NOT correct for non-quality and TF-based supplies that - as not expected - specify that the Max. Current Draw (the device can survive for not prolonged periods - no matter what the Output Voltage would be at that load) AND an (unloaded circuit) Output Voltage
─ ─ ─ ─ ─ ─ ─ ─
Other than that - as I understand - the OP uses the specific INPUT to a PROBE or PROBES of which 1 requires The Voltage and another The Current or the PROBE is eighter operated at Fixed Voltage or Fixed Current MODES -- since we don't exactly know - we can't suggest a speciffic solution . . . or a product . . . or a lack on a market

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hp1729

Joined Nov 23, 2015
2,304
Hi. I want a car that has constant velocity and constant acceleration, both at the same time.
To be specific, it must go 30 miles per hour at all times and accelerate at a rate of 1 MPH per second at all times.

Got it?
Certainly true, but more precise than is required or expected.
It looks like what he is describing is already on the market as a TENS unit. I could be wrong there. We will have to wait for his response.

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tcmtech

Joined Nov 4, 2013
2,867
My TENS unit puts out several hundred volt pulses that can be up to 80 mA so <6 volts at <6 Ma and in a DC form is way too low for a practical TENS unit.