Something is wrong with your math. You say the meter is 5 kohms which is in series with 3.7 kohms giving 8.7 kohms with 50 uA running through it for 0.435 volts. Ten you use 9 volts across the 22.5 kohm resistor... what? Or possibly there is something wrong with the circuit.
Or not.
Maybe when the numbers are right we can see.
-- Rick
Yes, but in that case the current is only flowing harmlessly through the tongue. If the soldier did it via this thumbs, the current would have passed across his chest - a very dangerous path. But would there be sufficient current to interrupt the heart's function to a fatal extent? Perhaps he had a weak heart anyway?
I also screwed up the switch position and got lost in the tangle of traces on the schematic. Here's an annotated version of the original Simpson 260-7 schematic, with the conduction path for Rx10K scale, which incidentally is the only one that uses the 9v battery.
I'll work out the correct equivalent series resistance later tonite. I gotta restack my firewood pile before it gets dark.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
No need to do it all formally. Just look at R20 at 114 kohms in series with everything else. This limits the current to under 80 uA no matter what.
-- Rick
New schematic, 2nd attempt, what can go wrong this time?
Rx10K scale. Current path shown in red on schematic above. All pots are assume to be at mid range. No warranty expressed or implied.
-lead --- 113K --+--- 5.6K ---+-------\ R20 | R21 | | | | | 17.3K R19 | | | 95K R1 Meter 1.1K R17 | 250 mv
11 ohms R16 | | | | | | | | +lead --- +9V- --+--- 3.9K ---+-------/ battery R2and 250mv. The meter resistance is: 0.25V / 50*10^-6A = 5K ohms
95K across 5K has little effect so I'll ignore R1.The meter contributes 50 ua of current (at full scale). The current
ignore R1).
R16, R17, R19, and R20 contribute:
resistance is somewhat larger than a dead short, which means the current will be even less.
That's considerably less current than what might be expected to cause cardiac arrest using DC (300 to 500 ma DC):
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
One of the major design challenges for this type of application is the avoidance of injury.
Stop being juvenile.
RL
You are on a roll. I don't know why you keep messing this up. I already showed you that the max possible current from just the 113 kohm resistor limiting current from the 9 volt battery is 79.6 uA. You made a mistake of assuming you can calculate the current through R16, R17 and R19 as if they were in series with R20 alone. Wrong!
Either live with the approximation I did or do the job properly. Do you really need to solve the full network to know that the current is perfectly safe? Upper bound is 80 uA even with all the other resistors being 0 ohms.
-- Rick
I once surpised myself with a 4.5V supply connected to two wet hnndles.
I would test 9v batteries on my moistend upper lip (mmm electricity!), reduced discomfort compared to tongue. tongue works for button cels.
-- \_(?)_
OK, battery, electrolysis, garbage bag to collect the H2 and O2. Small boom.
Ha- a MPH charging rate!
I did a little digging. I get ~690kJ (NIST) for a grenade with 164g of TNT-equivalent (the M26, the first I found), versus ~29kJ for a single
2.2AH 18650.They must've meant a full laptop pack, or the chemical energy of burning the LiIon?
Any which way, all nasty things to set on fire.
Cheers, James Arthur
When I was in boot camp, we learned to throw hand grenades over a wall and try to hit a jeep or some vehicle below. The instructor was very nervous about his job and demanded complete attention, and to look at only him, and not do anything until he said so. Poor guy. I hope they paid him a little extra for having trouble sleeping at night.
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