Search found 3574 matches

by MrAl
Tue Jun 19, 2018 3:59 pm
Forum: General Discussion
Topic: To evaluate performance of used 18650 cells...
Replies: 22
Views: 4330

Re: To evaluate performance of used 18650 cells...

I noticed that the Opus tester is used by many professionals. If you use a constant current source, that still leaves the problem of monitoring the time it takes to finish the test at the voltage level selected to stop testing. I believe it's 1v for single cells and 3v for the 18650s. The one I use...
by MrAl
Tue Jun 19, 2018 3:56 pm
Forum: General Discussion
Topic: Experimenting with Hot Glue..
Replies: 103
Views: 22066

Re: Experimenting with Hot Glue..

Hey MrAl, long time no see! I think you've hit the nail on the head with that last phrase. Just a comment on one of the threads to say, "Hey, we're working on it." would go a long way to ease the member's minds. Hi, Hello again, and yes it would be good ot hear something. I also see that this forum...
by MrAl
Mon Jun 18, 2018 10:03 am
Forum: General Discussion
Topic: Experimenting with Hot Glue..
Replies: 103
Views: 22066

Re: Experimenting with Hot Glue..

Hi, I've seen enough web sites like this one go through changes that always have a negative effect on certain things like pictures and text and math equations made with Latex. I can only think that the the people who make the web sites dont understand the importance of getting file formats and other...
by MrAl
Sat Jun 16, 2018 7:50 am
Forum: General Discussion
Topic: To evaluate performance of used 18650 cells...
Replies: 22
Views: 4330

Re: To evaluate performance of used 18650 cells...

Hello, The main check is the capacity. The capacity goes down as the cell ages so that's an indicator of how much the cell was used. To check the capacity, the simplest way is to use a constant current sink that draws current from the battery until it gets down to the lower cutoff voltage which is u...
by MrAl
Wed Apr 04, 2018 9:33 am
Forum: General Discussion
Topic: heat sink cooling
Replies: 5
Views: 1872

Re: heat sink cooling

I want to install a muffin fan on the heat sink of a stereo receiver, my question is in what direction should the air flow? Blowing in the heat sink or sucking heat off the fins? Thanks Moe Hi, In most cases it is better to have the fan blowing on the heat sink, as close as possible to the heat sin...
by MrAl
Mon Mar 12, 2018 2:29 pm
Forum: General Discussion
Topic: Soldering tarnished terminals!
Replies: 2
Views: 1802

Re: Soldering tarnished terminals!

Hi Len, I've used rosin flux in the past. I think it was G and C made for soldering, came in a small bottle. It comes with a brush, wipe it on, then solder. I've tried it as a test to solder an old penny and it worked pretty well, much better than with just the rosin core solder. Also, there are oth...
by MrAl
Sun Feb 25, 2018 1:36 am
Forum: General Discussion
Topic: Detecting a magnet... from a distance.
Replies: 23
Views: 5463

Re: Detecting a magnet... from a distance.

Hello, I like the replies so far, very interesting. The 'rube' one was funny too thanks to Len for that one. Detecting a magnet from a distance isnt that easy because it's a static field so you cant use radio methods like tuned circuits to detect some frequency. Here are a few lesser ideas though ju...
by MrAl
Sat Feb 03, 2018 10:03 pm
Forum: General Discussion
Topic: Very unusual desoldering method...
Replies: 9
Views: 2522

Re: Very unusual desoldering method...

Hi,

I get Godzilla to breath on the bottom of my boards and all the parts fly right off :smile:

It's not what you know it's who you know.

Or in this case, it's not what you know it's WHAT you know :grin: :grin:
by MrAl
Sun Jan 28, 2018 6:47 am
Forum: General Discussion
Topic: Adult Content!
Replies: 6
Views: 2165

Re: Adult Content!

Hi,

That's pretty funny.

I knew there had to be a good reason why we all got involved with electronics at one time or another. It's sexy :cool:
by MrAl
Sun Dec 31, 2017 4:42 pm
Forum: General Discussion
Topic: really old 4700uF capacitors
Replies: 9
Views: 2087

Re: really old 4700uF capacitors

I found a case of common electrolytic capacitors that I left unused for 30 years. Seems to still work. I found one that heats up. But the rest seem to still work. I'm reading about how capacitors have a shelf life of 3 years. How can this be? https://www.google.com/search?source=hp&ei=3yFJWqroN6nEj...
by MrAl
Tue Dec 26, 2017 3:06 am
Forum: General Discussion
Topic: Greetings!
Replies: 5
Views: 1871

Re: Greetings!

Hello there,

Merry Christmas and Happy New Year to you too, and all members of this forum.

Let's hope this year is a good one. For me it is a year of reorganizing my electronic parts and i've started already. So far invested over 150 bucks (USD) in storage containers of different types.
by MrAl
Tue Nov 21, 2017 6:40 am
Forum: General Discussion
Topic: Another simple amp question
Replies: 16
Views: 2539

Re: Another simple amp question

Hello there, Any circuit you build for this that is linear will always waste a substantial part of the input power and thus will drain the battery quicker. Since it is all about current mostly with battery operated stuff, you could study the current drain itself and see if you can improve something ...
by MrAl
Fri Nov 17, 2017 2:40 pm
Forum: General Discussion
Topic: Iron wire inductor
Replies: 12
Views: 2333

Re: Iron wire inductor

Lenp wrote:Never allow the facts to stand in the way of a good theory!
If the facts and the theory conflict, dispose of the facts.
Hi,

Yeah sounds like a good rule (he he) :smile:
by MrAl
Thu Nov 16, 2017 6:55 am
Forum: General Discussion
Topic: Iron wire inductor
Replies: 12
Views: 2333

Re: Iron wire inductor

Well, I was basing the post on my repair experience for older ovens. The transformer supplied both the filament and the high voltage, so to lower the filament voltage was a major redesign because the two windings were interconnected. I am sure, with an inverter design, the voltages could be adjuste...
by MrAl
Wed Nov 15, 2017 7:33 am
Forum: General Discussion
Topic: Iron wire inductor
Replies: 12
Views: 2333

Re: Iron wire inductor

A note about microwave ovens...and stuff! The magnetron is an all on, or all off device. The power is cycled to it with a varying duty cycle to control the cooking power. If the supply voltage were reduced, the magenetron would probably function outside it's design limits and it may fail, or simply...