T&L Publications

Nitric acid diluted to desired etch rate<p>or if you don't like acid<p>10ml Amonium hydroxide (oven cleaner maybee), 10ml 3% hydrogen peroxide, 100ml water<p>or if you want something you can actually get and won't burn you instantly<p>Ferric Chloride available at places that sell bare boards. <p>I d...

Most cable stations are analog NTSC, been around forever type. There might be a few digital stations but lets ignore that for now.<p>Direct TV broadcast in SD Standard Digital 480i which is about the same resolution as NTSC.<p>Generally digital stations are clearer because they cannot be viewed unle...

Do you want to light up a coin or do you want a compact light source the size of a coin?<p>Such light sources already exist in wristwatches and nightlights.<p>I can think of a few ways to illuminate a coin but making the coin light up itself would be a cool trick especially if the source was not app...

The LED will detect open circuits but not shorted circuits.<p>You will need to pass a current through the ignitor to determine its continuity. 12mA may be small enough. Aside from experimentally detrmining it, you can measure the resistance of the NiCr ignitors. You probably need 25W to 50W minimum ...

Choose a handfull of 5% 400 or 410 ohm and start measuring, you will probably find two at 402 before long but...<p>Value is only half the story. Given that it is to be used in a temp sensing circuit, I would expect you would want a resistor with a low Temperature Coefficient so that the value does n...

If you don't have aux input and RF modulators don't work well enough for you (they work fine for me, did you tune to the right station) then I hope it has a tape deck because a casette adapter is the only other way I can think of to get an audio signal in without tapping into a circuit inside the he...

Most Photo editing programs have tools to erase parts of an image. Better programs can merge in patterns from the surrounding area to fill in the hole left by the missing image. What programs do you have available to you.<p>In MS Photo editor (comes with windows or maybe the MS website), use the Smu...

I too am worried about the humid consiquences of an evaporative cooler.<p>To convince myself I considered that the cab of the loco is probably 10-30F higher than ambient temp outside. Even if the outside were hot and humid (not uncommon in summer in TN) the RH inside the cabin would be lower simply ...

Lets not let the clouds of global warming rain on the parade.<p>There already is much momentum and desire to develop alternative energy sources. Both Economic and ecologic forces are in line on that issue, even the Oil mongers wouldn't mind a little relief from other generation sources.<p>Although I...

It is a ground loop. THe head unit and your amp are grounded at different points of the chassis. tiny differences in the actual potental of ground between the two points is what you are hearing. This would not normally be a problem except that the shield in the line level cable (RCA jacks) is often ...

If your battery charger were equivelent to your power supply with respect to efficiency then there would still be an additional loss due to the battery's internal resistance during charge and discharge (yes they do get warm).<p>Where I live, you pay one electric rate all day long. Only the power com...

If you don't want to mess with batteries, a wall wart style transformer will do just fine. They come in AC and DC and a variety of voltages so check the specs printed or embossed on the side.<p>Almost any DC voltage less than 12V and more than 5V will work if all you want to do is light some LEDs. O...

OK, This guy is just a "Dealer" of the promised equipment. If you click on the link to the parent company "United Community Services of America" (sounds like a charity to me) in his FAQ the link is bad but searching on Google for the same turned up several more dealers.<p>This on...

A cheap PDA would have the calendar alarm function you need. I've seen the Palm III's going relatively cheap lately and toy-like models going for practically nothing. Not sure about the sustained alarm mode though because I don't own one.<p>You could tape it to the fridge and use it to remind you of...

just send an email to the subscription dept and they will mail you one if it was missed. See the main website for the address. I heard they had some "system problems" I just got May and June mailed to me.