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I have made a dry pile battery that has an output of 450 volts, BUT has an amperage of only 3 nanoamps.
I wanted to use the drypile battery to light an LED intermittently. The idea is that the LED would slowly flash for many years.
The amperage of the battery is so low that I can't use most electronic components. Most components will just act as a drain for the battery, without actually doing anything useful. I have charged a capacitor very slowly with the battery.
My thought was to try to use the battery to charge a capacitor, and have the capacitor light the LED intermittently. I could not figure out a way to charge a cap, and have the cap "switch on" to light the LED, and then automatically go back to charging the capacitor.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
By amperage, do you mean the short-circuit current? If it's that small, then the pile must have an internal resistance of 150 gigaohms. How do you measure the voltage?
The flashing light is trivial, and probably more luminous on average, if you use a neon glow lamp instead of an LED. Jut put an NE2 or equivalent (e.g. from disposable camera flash unit) in parallel with the capacitor, and you will have a relaxation oscillator.
By amperage, do you mean the short-circuit current? If it's that small, then the pile must have an internal resistance of 150 gigaohms. How do you measure the voltage?
***I used a Picoammeter to get the amperage. I use a Singer Electrostatic Meter to measure the voltage. I believe that your figures are correct, a dry pile has tremendous internal resistance.
The flashing light is trivial, and probably more luminous on average, if you use a neon glow lamp instead of an LED. Jut put an NE2 or equivalent (e.g. from disposable camera flash unit) in parallel with the capacitor, and you will have a relaxation oscillator.
*****I had pondered the use of a neon bulb. I was looking for something that would last for decades (or longer). As I understand it, a neon bulb will last for between 8 and 15 years. Perhaps even longer in "blink" mode".I was hoping for something that would last for at least 50 years.
My dry piles have already lasted for 5 years. There are dry piles like the Oxford Electric Bell that have lasted for over 150 years I hope that mine will last that long...or, dare I dream, longer. I suppose that I will be long gone before they fail to function.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
Zamboni wrote ... I had pondered the use of a neon bulb. I was looking for something that would last for decades (or longer). As I understand it, a neon bulb will last for between 8 and 15 years. Perhaps even longer in "blink" mode".I was hoping for something that would last for at least 50 years.
My dry piles have already lasted for 5 years. There are dry piles like the Oxford Electric Bell that have lasted for over 150 years I hope that mine will last that long...or, dare I dream, longer. I suppose that I will be long gone before they fail to function.
This is fun stuff! Please tell us more.
I bet the unpowered shelf life of neon glow lamps is more than 100 years, just like incandescent lamps. Nixie-tube clock enthusiasts could confirm that most 50-year-old nixies work, though some small fraction have gone bad with age. There's much less to go wrong in a 2-terminal lamp. Who knows how long non-hermetic encapsulated LEDs will last in benign environments? They seem OK in my 1970's handheld calculators and digital watch.
Neon specified operating lifetimes are similar to those of LED's. A typical part here: , run at 0.3 mA for a brightness of 1.40 mcd (omnidirectional), should be good for 50,000 hours. That amounts to 15 ampere-hours of charge passed through the lamp. How many AH of consumable material (per cell) are in your dry pile battery?
-Rich
[edit] I just learned a new name for the proposed oscillator circuit: What kind of capacitor are you thinking of? Leakage current in capacitor or lamp could be a deal breaker.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
Couple more things.
1. As mentioned before, your dry pile battery's anodes or cathodes must be chemically exhausted after some number of amp-hours or milliamp-hours. If 4 mAh (that's a wild-ass guess) then at 4 nA it would last for a million hours (114 years). Surprising that any battery could be short-circuited for years and have any juice left, but I guess that's what galvanic corrosion is all about.
2. Back to LED's. A few years ago I reported being able to see the light from an LED at steady-state current of about 12 nanoamps.
*****I make a (very expensive, lots of work to make) Device that uses a Zamboni battery to power a horizontal pendulum. The batteries that I make usually have more than 1500 volts per battery. Ocasionally, I mess up and the resultant (defective) battery only has around 500 volts. I was looking for something interesting to do with my "factory seconds". I have been working at making Zamboni Dry Piles for around 8 years. To my knowledge, I am the only peson in the world making Devices of this type. They look like this:
I bet the unpowered shelf life of neon glow lamps is more than 100 years, just like incandescent lamps. Nixie-tube clock enthusiasts could confirm that most 50-year-old nixies work, though some small fraction have gone bad with age. There's much less to go wrong in a 2-terminal lamp. Who knows how long non-hermetic encapsulated LEDs will last in benign environments? They seem OK in my 1970's handheld calculators and digital watch.
*****I am old enough, so you would think that I would have thought of Nixie tubes. I think you are right.
Neon specified operating lifetimes are similar to those of LED's. A typical part here: , run at 0.3 mA for a brightness of 1.40 mcd (omnidirectional), should be good for 50,000 hours. That amounts to 15 ampere-hours of charge passed through the lamp. How many AH of consumable material are in your dry pile battery?
*****I went to Radio Shack and got a neon bulb that turns on at 90 volts. I hooked it up and it did not light ;-( I am now going to try using a capacitor in parallel with the neon bulb. I don't know if the neon bulb (in an unlit state) draws off any current at all. I suppose that will be the next parameter I investigate.
What kind of capacitor are you thinking of? Leakage current in capacitor or lamp could be a deal breaker.
*****I am using a Mouser part number 871-B32652A2332J Polypropylene Boxed Capacitor (3300Pf) I understand that poly caps have very low leakage. I know the battery will charge the cap because I (foolishly) picked up the cap...and got shocked.
Thank you very much for you insightful suggestion. I don't know all that much about electronics and your encyclopedic understanding is very helpful.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
Thank you, Paul. I admire your Zamboni pile creations. We both have plenty to learn about neon lamps in nanoampere circuits.
Answers might come sooner by experiments than by searching the Internet. The latter just led me to this article about the dark effect
I wonder if your lamp is glowing at steady 4 nA, but too dim to see except with dark-adapted eyes, or only detectable with instruments? If the canonical oscillator actually runs, then with 3300 pF of capacitance the discharge energy is only microjoules per pulse. Might be visible in the dark. Let's see what happens.
Registered Member #834
Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644
Interesting research. I don't see how to use conventional electronic switches (mosfets probably) to make a DC/DC converter at this low power level. Even if a suitable design could be found, powered only by the HV supply, the leakage of the closed switches would be probably greater than the available current. The neon lamp oscillator probably works, but with switching at 90 V most of the power is wasted. It's probably possible to use a neon lamp as switch, driving another lamp (maybe a LED) through a step-down transformer. Note that neon lamps have a small leakage current, through the glass envelope and through the gas inside, that is frequently doped with a small amount of radioactive material.
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Light LED with 4 nanoamps
