T&L Publications

You can buy an eraser at the hobby shop that is used for cleaning a slot car track. Fixes essentially the same problem. A relay-contact burnishing tool can also be used when the oxide gets heavy. It's very similar to a miniature fingernail emory board, which you might already have on hand. {no pun i...

I took a look at the 4N25 datasheet; it does indeed operate in the IR region. Curiosity then got the better of me. From what I could come up with, infrared is used because it optimizes photosensitivity (e.g. wavelength matching, response time, and all that good etc. stuff). This ' Use Of Phototransi...

The only two reasonable answers I could come up with are 1) the ambient light theory and 2) it is easier/cheaper to achieve a wavelength match in the infrared spectrum. The first just seems sensible, the second is more semiconductor implantation physics that I've never really looked into. I wonder w...

The OP stated "I have a stand alone amp that it can be plugged into" not realizing that he already had the audio signal tracer being requested. All that's needed is the probes. Probably the easiest thing to do is replace the amp's input jack(s) with banana jacks and use regular ol' DVM pro...

A similar or identical L-meter is shown in the 2002 ARRL Handbook. The Spiwak article was available for a while as
a pdf file from the Poptronix website. I had gathered the parts together, but it's still waiting to be built. It's the
best non-microcontroller design I could find at that time.

I'd give eServiceInfo.com a try too.

The wrench types shown at the Park Tool and Amazon links...
instead of grinding the face, these edges can be ground so the wrench is not so wide.
Or request a recommendation from the manufacturer (Omron, Panasonic, etc.)

Hmmm... I'm not even sure what the standard nut size is for switches and pots. 3/8"? For a store-bought solution, bicycle wrenches seem like an excellent idea. I'm not sure, though, that they'd be available at such a small size as 3/8", which is considerably smaller than the usual pedal/ca...

This is maybe one of those "good news/bad news" situations, but among my circuits collection I have what the designer calls a Picture Tube Tester/Rejuvenator . I believe I got it from a ~40 year old television book. Unfortunately I won't have access to it until around the Thanksgiving holi...

Your best bet may be to obtain the specs for the Dugo part, then see what kind of equivalent you can order
from someone like Dalbani or the recently mentioned MAT Electronics.

2.5MHz ripple from a power supply? I don't recall ever running across anything like that. Are modern switchers
running that fast, or is this some "non-standard" app? The aforementioned LC filters and an LDO regulator with
good ripple rejection are the only options I'm aware of.

If you were interested in my method of archiving files and making a text file of backup-disc contents, I just learned of some helpful software. Courtesy of Don Lancaster and his What's New? blog. He says, -October 24, 2009 I was surprised to find out that there is no direct or obvious way in Windows...

Utilizing the radio's existing circuitry is a good plan. I'm not dead set on the LM386. I'd just tap into the already-built-and-wired volume control/amp/speaker of the radio. If the 1458 has a 40mA output source capability (my datasheet neglects to include this spec), using I^2R gives a measly 12.8m...

Hmmm... y'all are making a strong case. I have a buddy in the pool business so I could get
the acid for next to nothing. He's given me some before - the stuff will easily remove hard
water deposits and make your faucet fixtures look like new!

Does your "new" radio include a LM386 chip? For driving a speaker, I think I'd use it instead of the 1458. I'm not sure what kind of output the 1458 can deliver to a loudspeaker, but it's probably not much. The circuit as is provides about 300X amplification; the LM386 can give 200X with a...