What is a safe way to charge myself to 300V?

[seang]

Hi,

I am trying to charge my body to voltages around 300V. I have a high voltage DC power supply; I can set the current limit down to about 10uA. I was also thinking about using a series resistor between me and the output. Is this safe? How safe? Is there a safer way to charge myself !accurately!?

Thanks

 

[mgb_phys]

Why?

 

[berkeman]

Hi,

I am trying to charge my body to voltages around 300V. I have a high voltage DC power supply; I can set the current limit down to about 10uA. I was also thinking about using a series resistor between me and the output. Is this safe? How safe? Is there a safer way to charge myself !accurately!?

Thanks

You definitely need to tell us the context of this question.

 

[seang]

Hi,

I am studying some items related to electrostatic discharge. In the past, I have just walked around on a carpet for a while, or used a Van de Graaff generator to electrify myself. I need to get a bit more quantitative though.

I could just charge myself with the carpet, and use some nice way to measure my voltage, but I don't have the equipment to do this (an electrometer).

Thanks for your help

 

[mgb_phys]

Charging yourself to 300v isn't too much of a problem - assuming you take care to insulate yourself, make sure you are using DC (!) and have a nice big current limiting resistor.

Measuring the voltage is trickier.
The capacitance of a person is typically 100pf. So at 300V you would only have 30nC of charge on you. If you used a high-end Digital meter or scope with 10M input impedance, the time constant would be tiny.

 

[seang]

What's a good way to insulate myself? I've got rubber soles, is that good enough?

Thanks

 

[berkeman]

What's a good way to insulate myself? I've got rubber soles, is that good enough?

Thanks

Yeah, that's fine. It depends a bit on the humidity, right? Also, it sounds like an electrometer would be a good project for you to build for all of this, eh?

 

[seang]

Interesting suggestion; what kind of electrometer would be best to build?

I've built some amateurish electrometers, kinda like the one shown here:

http://amasci.com/electrom/e-field2.html

but that really doesn't offer the precision I need. Where I work, we have also have a rotating electrode type electrometer, but that hasn't satisfied me either.

 

[vanesch]

Be sure to calculate the resistor correctly. In no case you should be able to receive more than a few mA. Safest to stay below, say, 1 mA or so (even assuming you're a short to ground). For 300 V you'd need then at least 300 KOhm. Also be sure to have a resistor that can stand the voltage.

From 15 mA onwards, it becomes dangerous.

 

[seang]

Be sure to calculate the resistor correctly. In no case you should be able to receive more than a few mA. Safest to stay below, say, 1 mA or so (even assuming you're a short to ground). For 300 V you'd need then at least 300 KOhm. Also be sure to have a resistor that can stand the voltage.

From 15 mA onwards, it becomes dangerous.

Thanks for your input. I am able to limit the current output of the supply, so I should be OK. I will take your suggestion on the resistor anyhow, thanks.