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  1. Wow, awesome reply! I'll have to try that circuit out this weekend.
  2. It sounds like your on your way to revolutionizing the way our cars are powered. However, before you do that, maybe you should have a little fun first and consider a Nitrous kit for your car? At least you'll get to school a little faster! You might end up paying more for speeding tickets though.
  3. Doing a quick google search, it looks like NOx stuff is pretty bad. Nitrous Oxide (N2O) is laughing gas. According to http://www.alphanutrition.com/environment/carsepa.htm "Under the high pressure and temperature conditions in an engine, nitrogen and oxygen atoms in the air react to form various nitrogen oxides, collectively known as NOx. Nitrogen oxides, like hydrocarbons, are precursors to the formation of ozone. They also contribute to the formation of acid rain. Catalytic converters, the part of car exhaust systems designed to break down nitrogen gases are actually forming nitrous oxide - 300 times more potent than carbon dioxide as a greenhouse gas. Nitrous oxide makes up about 7.2 percent of the gases cited in global warming, the USA EPA said in a study published spring 1998. Vehicles fitted with catalytic converters produced nearly half of that nitrous oxide. Nitrous oxide also comes from nitrogen-based fertilizer and manure from farm animals."
  4. For running leaner, couldn't you a) reprogram the ECU or b) trick the O2 sensor to think that it is runner richer than what it really is? FWIW, I have learned from experience that it is not always a good idea to "customize" your car. Modifying your car engine can have unintended side-affects and also hurt the resale value. Running lean does increase nitrogen oxides. The problem is, is that air is comprised of like 75%-80% nitrogen and 20% of oxygen. So, if you use more air per gas, then more the nitrogen becomes a part of the exhaust. Unfortunately, without using pure oxygen gas, your nitrogen oxides do increase.
  5. Hi all, I want to make a very simple circuit. I have a few components that I have dug out of storage from when I took some electronics courses way back in college. I want to learn some stuff about transistors. The description of the circuit is to use a NPN transistor switch to power an LED light. The way I would envision doing this, is by creating an on/off switch at the base of the transistor and powering the LED light through the collector of the transistor. My question is, is this the right way to do this? What conditions do I have to meet in order to make my LED work? Another question is, where can I find a simple, free program where I can lay out my design graphically? I remember I used PSPice back in college to calculate voltage drops and currents. From what I remember, I had a student version at the time. Are there any free PSPice applications? Thanks! Mike
  6. Audioguru, I'm starting to see your wisdom in your recommendation to use the rechargeable battery that came with my phone. However, my morbid curiosity is getting the better of me here. I noticed an LC circuit in between the battery input for this chip (TPS61122, switching boost converter) and the SWN and SWP inputs. The SWP is the DC/DC rectifying switch input and SWN is the DC/DC switch input. What does this LC circuit accomplish? http://focus.ti.com/lit/ds/symlink/tps61122.pdf
  7. But the specs quote max voltage = min voltage = preset voltage = 3.6V. I thought that no matter what voltage you put in from 1.8V to 5.5V, you would always get 3.6V period. If this isn't the case, what kind-of voltage do you expect to get from a 5.5V input? I wasn't too concerned about getting a boost converter so much as getting a voltage regulator that was capable of being efficient, as well as creating a constant voltage at 3.6V. Also, what is LDO?
  8. Really?!? I had no idea. Maybe I should do that. I don't think that's really a feasible idea for me (just kidding). I always have to do things the backwards way first and then realize there is a reason for doing it the way it is done in the first place. That, unfortunately, is the only way I learn... Yours Truly, College of Hard-Knocks Graduate
  9. I have no idea! I hope so... I won't know until I see it. I'm getting a free sample off of the TI site. I had no idea that a little cell phone would be drawing that much power?! So maybe it's back to the drawing board. I found some battery holder's online through batteryspace.com. It is a little expensive for shipping, but the holder's themselves are cheap. Also, I didn't realize what you guys were saying about the rechargeables being only 1.2V each... so maybe I could use 3 "AA" rechargeable batteries for 3.6V and not worry about the regulator. However, I also like the idea of using 2 "AAA" batteries to cut down on size, so I am still interested in switching regulator.
  10. Can anyone recommend a 2 "AA" battery holder that doesn't take too much space? My current designs for a prototype will be to use a 2 "AA" battery holder, solder some wire to the leads to my little switching voltage regulator, and then connect the output of the voltage regulator to the cell phone battery terminals with very small aligator clips.
  11. Capacitors have a variety of functions. If you have an alternating voltage source (AC) and stick it in a circuit with the capacitor, the capacitor acts as a short-circuit. If you have a DC voltage source and stick it in a circuit with a capacitor, the capacitor effectively acts as a open-circuit. The interesting application in using capacitors is that if you connect a DC source to a capacitor then to ground, you can short-circuit all the unwanted AC elements without shorting the DC source. The converse of the capacitor is the inductor which acts exactly the opposite... The inductor acts as a short-circuit in a DC application, and as an open-circuit in the AC application.
  12. I have decided on: TPS61122: Synchronous Boost Converter with 1.1A Switch and Integrated LDO Is this a good choice? The specs: "3.6-V 95% Efficient Boost Converter with 3.3-V 200-mA LDO for 1-Cell LiIon or Dual-Cell Applications" 1. Topology: Boost 2. Min Vin: 1.8 3. Max Vin: 5.5 4. Min Vout: 3.6 5. Max Vout: 3.6 6. Preset Vout: 3.6 7. Iou Maxt: 0.5 8. Iout(2): 0.2 9. Operating Frequency: 600 kHz 10. Iq(typ) 0.04 mA Looks like the Max, Min, and the Preset Vout is almost exactly where I want it to be: near 3.7V.
  13. Thanks for the link. Looks like I'll have to do a little bit of research to figure out what all the parameters mean... in the meantime, what are some of the favorite and more popular switching voltage regulators out there?
  14. Thanks for all you guy's inputs. What a great forum board! I guess I have a some options: 1. Possibly using 3 "AA" batteries (I need to check the topped off voltage of my rechargeable battery). 2. Using a "series linear" voltage regulator to step a 9V source to a 3.7V source. 3. Using a switching regulator for a more efficient way of stepping down/up a voltage to 3.7V source. From this forum, I gathered this much about Switching Voltage Regulators... A switching DC regulator works by "pulsing" the input DC signal and then adding that pulsed signal into a steady DC signal by averaging the signal in real-time. Question: Wouldn't you need a transformer in the loop if you were going to step up the signal. E.g., my example of 3V to 3.7V?
  15. I guess I don't really care about the practicality about it! I figure there are worse things I could be doing with my mind and my money... and if I happen to learn a couple things on the way, how bad could that be for me? What non-linear voltage regulators can you recommend?
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