T&L Publications

new guy, In addition to what the other gentlemen stated: Center tapped transformers with 240V AC primary and two 120V AC secondaries are used for nearly all residential service in the United States. This system allows for the "Split Phase Distribution" of electrical current through your ho...

KamPutty, If you haven't already, I highly recommend you read the book "American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer" by Kai Bird and coauthor. The book has some great background information and references regarding the theoretical discovery of "black holes&qu...

Dean, If I go for the 7489 I'll buy several thrown in with a large order of alot of other stuff from Jameco. The cost of the shipping will be spread out and thus negligible. But, thanks for the offer on the 7489's. Mr. Al, I will look into the availability of a 2048x8 bit RAM chip & data sheet. ...

Dale, That is a great tip, thank you. Thanks for taking the time to look up the chip and reply. This project is going to be a rats nest as is, so anything I can do to cut back on the wiring is appreciated. As far as the chip being outdated: I hope it is available or at least that there is an availab...

Hello, I am planning my next project: A 16 bit (rows) x 8 bit (columns) TTL RAM. The TTL 7489 RAM is great and is almost exactly what I need but is 16 rows by 4 columns. However, I need 8 columns to store the full 8 bit instruction. I can use two TTL 7489 16 bit x 4 bit RAM IC's wired together to ge...

jwax Here is the basic claim: money varies directly with fossil fuel, or even simpler: money = fossil fuel. Here are a few examples of how fossil fuel is tied to money: An employee wakes up in the morning with an alarm clock that was manufactured by machinery built and operating on fossil fuels, he ...

Electric cars require huge fossil fuel expenditure to manufacture and maintain and operate. An electric car that costs $100,000 uses up about 5 times more fossil fuel resources to manufacture and operate than a gas operated car costing $20,000. But what fun to drive!!! I love driveing electric vehic...

Robert, The function generator I recommended to zotdoc has a range from 1 Hz to 1MHz. That should be plenty. The human ear can detect sound frequencies ranging from a few Hertz up to about 20 KHz (although I lost the upper half of that when I served in combat contigency company Alpha 1st Tank Battal...

zotdoc I built this function generator: http://www.electronickits.com/kit/complete/meas/fg500k.htm It will give you the frequency range you are looking for, is very easy to build, very high quality, very easy to use. The only problem I have (and this is for all of the low frequency circuits I have b...

david753: Here is an idea using your magnets: Each die could to be loaded with 3 elecrtro magnets. Each electro magnet would have its axis normal to opposing die faces and would need to be remotely switched on or off. The table surface would also need to be magnetized with polarity reversible. Here ...

Philba,

Does the diode across the relay prevent arcing on the relay contacts and any problems associated with that?

When the next door neighbor's kid drives by our house, his windows rolled up, our windows and doors closed, the power of his stereo still rattles our 2 story house with bass thumping. It seems like there must be some serious power there somewhere. It also seems like all the music players in kid's ca...

Chris,

It's true that people need metals and minerals in their diet. However, it takes nature millions of years to break down raw metals (iron for example) into dietary metals.

Boris, try looking for a good Radio Shack again, it'll have about 50% of most of the common components you'll need. Fry's Electronics is out here on the west coast, not sure if there where you are yet, but Fry's is like the Walmart (do they have those in PA?) of the electronic components industry. W...

One other thing I just realized that was implied in several of the responses but stated below:

If the neutral is grounded to the chassis, and there is no separate ground conductor, then the GFCI will not trip when a human touches the hot and the chassis. The person will be electrocuted.