Did you ever try the light bulb instead of a fuse ?
Depending on the normal load, you can use a 100 watt light bulb (wattage to
vary depending on normal current usage) in place of the fuse. When the
light bulb glows much dimmer or not at all then you have found the problem
that usually blows the fuse.
Putting the amp meter across the fuse will not depend on the load, but the
actual ammount of current that can be sourced. Say the normal load is only
10 amps, your meter is good for 20 amps, but the source is good for 100
amps. If you have an almost short at the load, close to 100 amps is going
to try and pass through your 20 amp meter which is now toast , or hopefully
the internal meter fuse blows.
You should only put the amp meter in line when you get the fuse to stop
blowing. Then it should be safe to see how much current is actually being
I had a 100w, 150w and 200w bulbs that I soldered test leads with
alligator clips to when I was working as a bench tech back when
appliances and TV sets used a lot more power. In the past 20 years,
most of the service work I've done has been mobile and not a good
place to have glass bulbs bouncing around in a vehicle. I'm sorry but
I keep assuming others would do what I do without thinking. The light
bulb in series with a Simpson 260 was SOP when working on two way radios
to check the DC current draw. A shunt was needed for AC current tests
since those meters would only test up to 10 amps DC. A separate AC
ammeter worked for bench testing. I had variable power supplies that
indicated voltage and current being drawn by equipment when bench
testing plus those power supplies had adjustable current limits that
would drop voltage to zero when the limit was reached. The small
resettable circuit breakers I used were put in series with the DMM when
testing current draw. I repeat, never use a DMM to check current in line
if you know it will exceed the safety limits of the meter. Test leads
can melt or have the tips burned off. It's not a problem to put a DMM
across a fuse when testing a radio being powered by a 12vdc power supply
which is rated at 3 amps and has a built in circuit breaker like the
small power supplies sold by Radio Shack for many years. It's been a
while since I've been in a Radio Shack store to buy discrete components
or batteries. If I'm working on a small AC appliance that would draw 5
amps/600 watts,(look at the label). The small circuit breaker in series
with with a DMM having a 10 amp range is completely safe unless you are
dumb enough (like me) to touch the exposed test clips and get a shock.
Even if the small circuit breaker is not used and the appliance has a
dead short, the 20 amp breaker supplying power to the outlet you are
plugged into will trip. The small circuit breakers
I once put together on my own are now sold at supply houses with the
pigtails and test clip already on them. When repairing electrical or
electronic gear, the best test equipment are your eyes, ears and nose. ^_^
re: "...unless you are dumb enough (like me) to touch the exposed test
clips and get a shock."
...or the banana plug on the end of a jumper cable.
In my case it was the second week of USCG Electronics School training. On
the worktable in front of us, we each had a 400 VDC power supply training
device which was plugged into a power strip.
There was a ~4" jumper cable, with a banana plug on each end, that
connected two sections of the power supply. The jumper could be pulled out
to break the device down into smaller sections for troubleshooting
training. Basically you were removing the load. The normal procedure was to
shut the power supply down, pull the jumper and then power it back on.
Heck, I don't need to go through all that. I'll just hooked my finger into
the loop and pull the cable out. So, with my forearm resting on the
chassis, I hooked my finger into the jumper and pulled. Too bad one banana
plug (on the output side) was a lot looser then the other one. With input
side still plugged in, the loose end flipped up and laid against my thumb.
With my arm laying on the chassis (read: ground) I became the new load for
the 400 VDC.
My arm spasmed and I couldn't pull it away from the chassis. Instinctively,
I reached out my other hand to pushed the chassis away. All that
accomplished was to cause the current to flow from one hand to the other
through my upper body. I was holding a 30 lb power supply up off the table
as if it was weightless, yelling "Turn if off! Turn it off!" as my whole
upper body spasmed.
The guy at the table in front of me turned around and grabbed the power
cord in an attempt to unplug the device. Unfortunately, the power strip was
not secured to the table so it just came up with the cord. The guy next to
me reached over and slapped the power strip back onto the table which
unplugged the device.
I dropped (actually, threw) the power supply onto the floor and they drove
me over to the infirmary for an EKG. Other than the burns on my hand, I was
When I came back to class the next day all of the power strips had been
screwed down to the work surfaces and 2 other guys had quit electronics
school after witnessing my near demise. They quit ET school and I went on
to work on devices that had power supplies in the range of 25KVDC.
Luckily (?) I still have the scars on my hand to remind me of how stupid I
was. I've been a lot more careful since then.
work on the set in front of the customer who had an odd yet concerned
look on her face. I've been shocked, zapped and burned more times than I
can count but I never, ever let my guard down around high voltage high
current power coming into a building. When I worked as an electrician,
my superintendent got a tingle when using an old wooden hot stick while
we were connecting some 4,160 volt pad mounted transformers for the
underground electrical system we were building. If it had been 13.8kv I
doubt he would have gotten just a tingle. All my ladders and push poles
are fiberglass because one never knows what you can run into around
power systems. I learned long ago to work on everything as though it was
energized because it a good habit to get into. One thing I really hate
is when I've been working in hot weather and because I sweat like a
thunderstorm, I wind up soaking wet with all my clothing soaked and the
sweat dripping on the floor. You can tell where I've been by the wet
areas on the floor. In this condition, I've had my sweat soaked shirt
tail touch a ground while I was working on a panel. Salt water and sweat
conduct electricity very, very well. o_O
On Wed, 25 Sep 2013 16:19:51 -0500, The Daring Dufas
As a kid I had salvaged a power supply out of an ancient TV that
didn't use a flyback system - the main power transformer had taps
from, IIRC, 3.5 volts to 25000 volts. The high voltage was at the
opposite end from the low voltage. I needed the low voltage to test a
small motor I was working on, but I grabbed the wires on the wrong
end. I must mention the basement ceiling was something like 5 1/2 ft
to the floor decking, about 42 inches to the bottom of the joists. I
was just under six feet tall at the time. I straightened up fery
quickly and my rock-hard skull caught the end of a nail that held the
1/4" unserlay to the sub-floor, and I popped the head of that nail
through the linoleum flooring in the living room above.
Sounds miserable. I'd not want to hit a nail
with my head, in any situation.
Christopher A. Young
Learn about Jesus
On 9/25/2013 11:42 PM, firstname.lastname@example.org wrote:
====================================20 Items to Hoard Check list
When a crisis is brewing, making a comprehensive list of supplies is no
easy task… neither is purchasing them.
As panic spreads, super market shelves will be stripped bare in a matter
of hours. Contrary to popular belief, super markets don’t have tons of
excess inventory. What you see on the shelves is what they’ve got in
We see it almost every time a major hurricane targets a populated area.
Desperate shoppers buy up every last can of beans, flashlight, and
bottled water in a 50-mile radius.
If you’re smart, you won’t be standing in line at the grocery store when
the SHTF. You’ll already have that taken care of…
Because you’ve read through this checklist to make sure you have
everything your family needs to survive a crisis. Here are our Top 20
Items to Hoard:
1. Rice – Dried rice has an incredibly long shelf life, making it ideal
for storage. In nutritional terms, rice is rich in starch and
carbohydrates. It’s also a good source of Vitamin B, iron, and protein.
2. Beans, Lentils, Black-eyed peas – Legumes are a great source of
protein, iron, and dietary fiber. Like rice, which they’re traditionally
served with, dried beans have an exceptionally long shelf life.
3. Candles – You’ll probably never read a disaster preparedness list
that doesn’t include candles, and for good reason. A good stock of
slow-burning emergency candles is a survival essential, as well as
something to light them with.
4. Cigarette Lighters – I recommend stashing a combo pack of at least 6
lighters in your stockpile. In a power outage, these guys can become
very, very important. The can also be very easy to misplace.
5. Pasta – Pasta stores well, has a long shelf life, and it’s loaded
with carbohydrates. It’s also easy to prepare. Not to mention, pasta
pairs well with lots of other items on this list.
6. Peanut Butter – Hoarded by everyone from college students to doomsday
survivalists, and for many of the same reasons, peanut butter is a
tasty, shelf stable source of protein that pairs with lots of other items.
7. Can Opener/Multi-Tool – It’s a good idea to carry a survival knife,
but it’s a great idea to carry a quality multi-tool, like a Leatherman.
A Leatherman comes in handy almost every day under normal circumstances
and could be used as a weapon in a pinch.
8. Dried fruits, such as raisins, apricots, and papaya – Dried fruits
are a great source of nutrients, calories, potassium, and fiber. They
can also be added to nuts to make delicious trail mixes.
9. Energy bars – Since these bars are typically loaded with carbs and
protein by design, they’re actually a good choice for your survival
storage (maximum nutrition with minimal effort and prep).
10. Canned soups and chili – Canned soups are easy to prepare and offer
a nice variety of ingredients for the effort. Look for low-sodium
options. Premium brands may be healthier, but value brands will make
your money go further.
11. Gauze/Bandages – For more serious injuries, you’ll want to keep a
supply of dedicated gauze and bandages.
12. Rubbing Alcohol – Rubbing alcohol burns on an open wound, but it is
a great way to sterilize instruments, surfaces, and the skin surrounding
13. Batteries – Obviously, you’ll need to coordinate your battery
storage plan with any of the flashlights, radios, or other devices you
may keep in your emergency stockpile. Batteries will last longest in
cool dry conditions, but should be rotated out of your emergency supply
on a yearly basis.
14. Toilet Paper – Running out of toilet paper is annoying in any
situation. But you certainly don’t want to run out in a shelter-in-place
crisis scenario. My advice is to get more than enough. Life can get messy.
15. Trash Bags – Trash will still need to be properly disposed of, even
in a crisis. In fact, trash bags are even more important in a crisis. If
running water is unavailable, trash bags may have to double as a toilet.
Don’t skimp here.
16. Firearms – Last but certainly not least, you’re going to need some
type of weapon, just in case. It doesn’t have to be a gun, but then
again what else are you willing to risk your family’s safety on, a
sword? Pepper spray?
17. Drinking Water – Most experts recommend a 2-week supply of water in
your emergency storage. A 72-hour supply is the bare minimum. A water
filter can help you extend you supply by allowing you to reuse cooking
18. Hand-Crank Radio – Hand crank radios offer the ability to listen to
important communications when power and cell networks are down. Some
hand crank radios even offer a USB charging functionality.
19. Camp Stove – There are a million options available for this purpose
– everything from handy backpacking stoves to heavy-duty outdoor ranges
– but it’s hard to beat the old self-contained Coleman camp stove.
20. Flashlights – When it comes to flashlights, I have two
recommendations, and neither one is expensive. First, find a comfortable
LED headlamp. Second, rather than finding the brightest, most high-tech
available, invest in a Maglite that runs on simple AA batteries.
I agree with the rest, but this in particular. Might be safe across the
fuse in something like an amplifier. Power fuses you had better have a
CAT rated meter, as in another post. A meter would seldom have a high
enough amp scale anyway.
On Sat, 21 Sep 2013 20:34:59 -0500, The Daring Dufas
The VD is Voltage Drop. You check across a fuse in energized circuit
on the volt scale to see how many volts are dropped across it. If it
is close to zero, the fuse is probably good (or the circuit is not
closed). If you see full circuit voltage, the fuse is bad.
This is not an answer to your quiz, but we used to test BFR (Big Fracking
Resistors) by banging them on the edge of the workbench.
These were foot long, 1" diameter ceramic resistors used in LORAN-C
transmitters. Before we'd meter them, we'd bang them on the edge of the
workbench. These resistors had a habit of getting brittle before they
failed. We preferred that they cracked while out of the transmitter rather
than when they were in a 15K VDC circuit.
The arc across a cracked resistor makes a lot of noise.
The best fuse tester I have used is a Fluke T3. You can go across a fuse in
a circuit and it will automatically show if the fuse is ok by showing
continuity or if it blown it will show voltage if there is any voltage
above 24 volts. Meters are nice in some cases, but this little tester is
almost impossiable to blow as long as the voltage is under 600 volts.
Nothing to turn on, turn off , or adjust.
I used a good old Wiggy for years when doing a lot of electrical work
and I'm sure I could find it in my stuff if I haven't lost it.
The Fluke T3 is a modern variation which looks like the old Wiggy.
Anything I use will have a CAT rating when working on any voltage above
about 50 volts.
Fluke put out a film that shows what can hapen with the less expensive
meters when used on equipment that can have a very high current capacity.
Even putting the wrong fuse in a meter rated cat3 or more can get you in
trouble. The beter meters will have a fuse in the ohm meter section. If
you hapen to put the meter in the ohm or amp setting and get across a
voltage source and the fuse blows, but the not rated fuses can arc over and
have the effect of not blowing. In almost no time the leads insulation
melts and you are across the voltage source. Or the leads explode from the
That little Fluke T3 tester is very handy. Small enough to slip in the
back pocket. They also make a T100 multimeter about the same size that
works very well . It will do voltage and up to around 1000 ohms and has a
provision to act like a clamp on ampmeter. It is also almost impossiable to
blow up. We used them at work and would often go across fuses on 480 volt 3
phase circuits. Most often just using the ohms setting and going across
fuses. Never did see one go bad even when the fuse was blown. I probably
checked thousands of fuses this way on running equipment.
That's going to keep me awake, wondering.
I hope you give the answer, eventually.
After the suitable amount of begging, of
Christopher A. Young
Learn about Jesus
On 9/21/2013 9:34 PM, The Daring Dufas wrote:
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