T&L Publications

Selling Kits is a delicate balance between cost and features. Most of us are aware that a gadget in kit form cost far more than the equivelent mass produced item due to the cost of kitting, labeling and producing an instruction sheet (nevermind supporting your customers)for such a low volume market....

Usually, I've seen others post such requests right here in this section of the BBS and such requests have been warmly recieved. Though, I don't know if anyone ever has in fact done a design for barter or money due to a hookup here. <p>So long as these requests come at the same pace, I don't see a ne...

For low current and used as an interconnect, use a plain resistor model. For higher current used as a heating element it would have to be a resistor that takes into account self heating and temperature coefficient.<p>I is a function of R and V, R is a function of Temp, Temp is a function of I, R (an...

The detail about the end application helps. I was beginning to think that you did know about cars but like the fuel pump, had a bottleneck in electrical ideas.<p>Increasing the wire gague (size) may reduce a voltage drop if the current in the wire is very high. Not sure what kind of current a fuel p...

Anything made to work in a car should already work equally well at both those voltages. 11.5 to 12V is what you get from the battery when the car is off and 13 to 13.5V is what you get from the alternator when the car is running.<p>Increasing DC voltage a small amount is suprisingly technically diff...

Are you looking for a recommendation for CAD software or on an inexpensive PCB fab<p> www.pcdandm.com is a trade magazine with links from its website for vendors. Click on the current advertizers link<p>I use www.pcbnet.com because I can get 5 two layer boards delivered for $100 full spec, standatd ...

An LED sequencer can be made with a counter chip or a bunch of flip flops (for a little more control)<p>Basically the chip is clocked by an oscillator (can be a 555 circuit) which causes the output pins to change state in the designed sequence. Each output pin drives 1 LED. <p>By designing a counter...

Most tasks in electronics require little mobility. I spend most of my day at the PC doing CAD, customer support, searching for and researching parts on the web and lurking in this forum. When not in front of a computer, I may be seated at a bench assembling prototypes or making measurements.<p>Only ...

In such a simple circuit, it makes no difference whatsoever the order the LED and associated dropping resistor.<p>In addition to using ohm law, you should also add up all the voltage drops in the loop, they should add to 0 and all the currents in and out of any node should also be 0. These three con...

Only the rules of polite society apply here.<p>In my opinion, any subject or question commercial or private within the scope of the magazine's subject is fair game here. (and a bit more)<p>I also feel the posting of links that are ultimately commercial in nature is fine so long as the link was liste...

Any temp controller has inputs for one or more thermo couples, outputs to control the load (usually a relay) and a way to power it.<p>Look for one that works at 110V to power it up and use a relay with 110V coil and 220V rated contacts. This will alleviate you from needing a DC supply to power it an...

synesthesia right? <p>Do you want to dimm all of the lights at once or dim each light individually acording to your program.<p>The first route is easy, you just need to put a variable resistor or dimmer on the common return line for all the bulbs. (this is really cheap). Note that most dimmer switch...

You say the inverter circuit protection trips upon power up of the AC powered switching supply you have plugged into it. Does it power the PC ok after it is powered up or have you ever gotten that far.<p>If the Inverter were starved then you could put a cap in parallel with the DC input but that wou...

Go the home depot and look for a filter cartrage. The one I am thinking of is about 18" and 2" or 3" in diameter (a guess from memory). Use an activated charcoal filter for taste and oders. If it were silty you would need a paper filter first but this is not nessary here. The filters ...

I assume you mean a non-contact sensor suitable for use turning on the windshield wipers. I think it has something to do with IR light and how light reflects differently off wet and dry glass.<p>see auto.howstuffworks.com/wiper4.htm and the associated PDF link on the same page.<p>TRW makes a sensor ...