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Getting old

Similar to Arfa not being able to see parts on the floor... Yesterday, I decided to connect a simple circuit to tell me if I left the garage door open when going to bed. I found a reed switch and matching magnet in my junk box as well as an LED (with built in current limiting resistor) and a left over wall-wart power supply. After connecting it all up I realized the LED was on when the door was closed rather than open which I preferred. I didn't have a N.O. switch but I did find an old piece of breadboard and a 2n3904 transistor. All I needed was a 10K resistor to use as a pull up to make my own inverter. I also wanted to add a 470 ohm R in series with the LED to lower the current a little. Bottom line: It all works well, but took way longer than expected. Why? It took a long time to find the right R's in my old box containing hundreds of 1/4 w R's. The

1/4 Watt resistors in my box clearly have shrunk over the last 30 years! And, the color stripes have all faded to the same shade of darkness, too. I kept pulling 4700 ohm R's from the box when looking for the 470 because the red stripe looked brown to me. I'm glad I don't do this for a living anymore! Pat
Reply to
Pat
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"Pat" schreef in bericht news: snipped-for-privacy@4ax.com...

Well, growing old may not be funny. Being old even less. But it seems to be the only way to live longer and most of us want to.

As for the colors on resistors, they are often unreliable even on new ones. Even with perfect eyes that can see all colors sharp and clear you often can only guess what color it is supposed to be. So I always keep my Ohm-meter nearby.

petrus bitbyter

Reply to
petrus bitbyter

A long time ago, resistors had the value printed on them. I believe they were Ohmite resistors.

Reply to
tm

"Pat"

( snip)

** The coloured bands on resistors do fade with age and red/brown confusion is common depending on the body colour.

You DO need a bright light, NOT incandescent but fluoro with a "daylight" white character.

A small magnifier may help too, but checking with an ohm meter is the safest.

Particularly with any 1% types.

... Phil

Reply to
Phil Allison

If you've ever gotten a package of 'mismarked' resistors; you will ALWAYS check with an ohmmeter. Especially watching the effect of putting 10 ohm resistors into the location meant for the power dissipation of a 10k ohm resistor! Or, the package I once got with the color bars painted in REVERSE order?! But since covered the whole body, not immediately discernible.

Reply to
Robert Macy

"Robert Macy" "Phil Allison"

If you've ever gotten a package of 'mismarked' resistors; you will ALWAYS check with an ohmmeter. Especially watching the effect of putting 10 ohm resistors into the location meant for the power dissipation of a 10k ohm resistor! Or, the package I once got with the color bars painted in REVERSE order?! But since covered the whole body, not immediately discernible.

** How do you tell the coloured bands are in the reverse order ????

Does the value change dramatically if you apply ohm meter leads the other way around ?

... Phil

Reply to
Phil Allison

I ordered some blade type fuse holders and fuses from a Chinese eBay vendor.

After 2 months they had not arrived, so they sent me another set. Eventually I got both sets, with any indication of when they were mailed or from whom removed.

The fuses are small flat clear plastic cases with a fuse element inside, and a color coding for the amperage and the number stamped on top.

The assortment was supposed to be 5, 7.5, 10, etc. However it seems that the 5 and 40 amp fuses are both the same shade of red. One batch came with 5 amp fuses, the other came with 40.

To really mess things up, the wire on the fuse holders was stated as 3.5mm, and they came with 20 amp fuses. The wire was 3.5 mm including insulation, the conductor was closer to 1.5mm. I would not want to use a 20 amp fuse with it.

Since I already had (and paid for) two sets of the holders and fuses, I notified the vendor of the problem but did not ask them to replace anything.

Last I looked, they had not updated their listing.

Geoff.

--
Geoffrey S. Mendelson,  N3OWJ/4X1GM/KBUH7245/KBUW5379 
It's Spring here in Jerusalem!!!
Reply to
Geoffrey S. Mendelson

or.

lly

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,

ng.

Here is the Chicago area of the USA also. Electronics taking a back seat to getting the tomatoes, beans and other veggies planted.

Reply to
hrhofmann

On a tangent- how do people here organize their resistors and other parts?

By range or by the first significant digits?

I don't do repair work full time, so I just have boxes of stuff, mostly in smaller bags already marked with values since I just get those "engineering sample kits" from digikey to cover common ranges of stuff.

I can't stand the screech of those little plastic parts drawers so I never use them.

Reply to
Cydrome Leader

That's how I do it for 5% parts. The third band selects the drawer.

tm

Reply to
tm

Two values per drawer, with a divider. From 1.0 ohm to 22 Megohm. Most of the drawers are close to full.

Wax the bottoms of the drawers and they are very quiet.

Reply to
Michael A. Terrell

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