T&L Publications

Dave,<p>Are you planning on installing your Mac into your car? I have already explored all the power supply possibilties when I installed a PC in my car. I eventually found it easiest to use the power invertor instead of trying to design and build a DC/DC power supply strong enough to run it. If you...

I have been working on a 556 timer relay design. Originally tested the design with a tester circuit board. Then soldered up a permanent device. However, it appears that the trigger input is always grounded. I removed the 556 timer (socketed), and put it back in the tester board. I connected Vcc and ...

I read some of it, but not all. Several things stuck out to me that I did not agree with. He said, "let man rule man, not money". He very much suggests that money is basically the root of the problems. This isn't exactly true by the way I see it.<p>I think the problem is that people want t...

Thanks.<p>Actually, I have never worked with or looked at flip-flops. Honestly, I "learned" (term used very loosely here) 555/556 timers just for this one project. So far, I $30 into th 556 design, and almost have it all soldered down. I'm not sure what leakage current is. I'm guessing tha...

ok, I built it without the extra 2k resistor and diode. I used a 556 timer, and ran the output to the trigger of the second half of the 556. It seems to work just fine. However, I've got to get the cap/resistor combination on the first hreshold/disharge so that it does about one hour. I have a 4700u...

Ooops, sorry, It was supposed to go straight to the right one. Its the one titled: 555 timer Mono stable (one shot) circuit<p>There are two diagrams. The one on the right is designed for the long input. However, I'm thinking that in my situation, the 2K resister connected to the + supply and the tri...

Well, obviously there are several different ways to get the same results. Here's the circuit diagram I found and was planning to use (on the left). However, he has different values for caps and resistors, and he has a diode and another resistor in his design. Are they needed?<p> http://ourworld.comp...

Thanks.

Thanks everyone,<p>I eventually broke down and looked for the simplest solution. I ended up with a standard ATX power supply running off a DC power invertor (I already have both), and a system board that supports "last power on state" (will boot automatically when the power is reapplied). ...

Thanks. I doubt I can get the scematics for this amplifier. It's a car audio amplifier, and they typically are protective about their designs. This one happens to be an Xtant 302a. Xtant is definitely not going to give out the schematics for their gear. Since this things dead one way or another, I'l...

This should be very basic and easy. I need help identifying a resistor on a circuit board. I also need suggestions as to where I can buy replacements.<p>I have an amplifier that released the genie. Two power mosfets were blown. I ordered identical replacements and soldered them back in. During furth...

So what you're saying is, that to increase DC voltage, I'd need to use some sort of switching device to turn the DC into pulses, then pass that through a capacitor, then to a transformer (where the voltage is actually increased), then rectify it back into DC. Hence, I'm back to using my DC/AC invert...

I'm confused again. But I guess what I was misunderstanding is that I need the transistor turned either On or Off, not partially on, or else the heat will kill it. Even with a beefy heatsink? We're talking a large aluminum heatsink if needed. And what about the high power regulators, like the ones a...

Hmmm, I think I need more knowledge about power transistors and mosfets. There are alot of terms used (both here and while looking at component specs), and I don't know what they all mean. Obviously they have significant importance. What is the dropout voltage?<p>And what about this regulator... htt...

The goal is to install a computer in my car. Yes, I know that 12vDC ATX power supplies are available commercially, but the cheapest is $130, and specs out at 14A and 10A on the 3.3v and 5v rails. It's not strong enough to power much more than an ITX or PII system. I originally wanted to modify an ex...