Jump to content
Electronics-Lab.com Community


  • Posts

  • Joined

  • Last visited


Everything posted by MP

  1. This topic has been moved to Electronic Projects Design/Ideas. [iurl]http://www.electronics-lab.com/forum/index.php?topic=10508.0[/iurl]
  2. Converting gray code to BCD does not make much sense. I think you mean binary code to gray code or gray code to binary code conversion, which is quite simple. Click on the image below for a larger view. MP
  3. Here are the complete instructions from a kit based on this chip: http://kitsrus.com/projects/k127.pdf Your LCD display should have corresponding pins with the same markings. This instruction set is much more complete than the Intersil data sheet, and explains the voltage divider as well. Hope it helps. MP
  4. Vivek, The Shure SM58 provides a positive signal on pin 2 with respect to pin 3 when pressure is put on the diaphragm (when sound hits it). Pin 1 is connected to ground. To connect this microphone to an unbalanced mixer, you just connect pins 3 and 1 to ground and use pin 2 as your signal output. This is all you have when you purchase a cable with XLR on one end and 1/4" phono jack on the other end. You will not see any difference in the output unless you are running massive lengths of microphone cables. MP
  5. MP


    Hi Taz, Here are some links for tutorials and formulas. This should keep you busy for a while. http://tpub.com/neets/book7/25f.htm http://webtools.delmarlearning.com/sample_chapters/04.pdf http://www.technologystudent.com/elec1/tranfrm1.htm http://www.cotc.edu/rromei/Trans%20formula.doc http://www-ee.uta.edu/online/adavis/ee5305/transistors.pdf http://www.qsl.net/wa7zcz/area2/page26.html Have fun! MP
  6. The size of the pad will be mostly determined by the package and the hole size. You will have to figure this one out. If you want to have a 5 mil ring for solder, you have to add 10 mil to the size of the hole that will be used. This is the pad size. As a standard, through hole pads are round with exception to pin #1 on ICs and headers. Pin #1 is denoted with a square pad in these cases. Many programs will give you an option to use an oval pad. This is just a design preference that makes manual soldering a little easier. Since surface mount chips have pins so close together, you will usually see a rectangular pad in these designs. This allows you more solder surface without getting too close to the next pin. hope this helps you. MP
  7. Hi Rob, Whichever side of the board you are not using for traces, can be left unetched, (except for places where the through hole components come through it. Otherwise, everything would be connected to ground). Just etch around these holes so that the components do not touch the ground plane except places where you want to connect to the ground plane. MP
  8. Use of a circuit board allows you to have a ground plane on one side. This will help keep noise to a minimum since all of your traces will be as close to the ground plane as the thickness of the board. If you can't get or make a circuit board, you can attach copper foil to both sides of a blank perf board with spray adhesive, draw out your circuit, cut out the unneeded parts, and push the leads through the foil where a hole exists. Instant circuit board, almost. MP
  9. It is actually a combination of smaller tank and more circulation from the bubbler. The smaller tank causes more efficiency of a small heater (more wattage per mass to heat up). Then you have the bubbler action which aerates and moves the water more than you would with an aquarium. Again small mass of water, more circulation. This will pull the heat away from the heater more efficiently so that the internal thermostat does not turn it off prematurely. Thus, the entire body gets more overall heat than what you would see in an aquarium with it's larger mass of water and poor circulation. My larger etch tank holds approximately 17 to 18 liters of etchant. For this, I use two heaters. One on each side. Not that two heaters are required fo the temperature, but to keep things even from one side to the other. I also have a very aggressive bubbler system. However, I have had one of the small hobbyist tanks in the past, like what you see at www.circuitspecialists.com and they are just as efficient with their small tank, fish aquarium heater and fish aquarium bubbler. It is all the same principal. BTW: Gogo is correct. 32C will help the etch process considerably over cold etch. It is around 90F, but you don't want to get ferric too hot or it will vaporize and you will breath it. MP
  10. All of the ones I have purchased have an adjustment on the top of them. You just set it according to needs. For etching, this is usually near the top of the scale. There is no temperature sensor inside these heaters. It is a metal strip that works like a mechanical thermostat. When the heat expands it enough, it triggers the switch. It is possible that you do not have enough bubbler movement in the tank to allow the heated etchent to move away from the heater and to the other side of the tank well enough. If you have poor circulation, the heat around the heater will turn it off prematurely, causing a lower overall temperature to the etchant. My tank can hold 4- 12" x 12" panels. I use 2 of the longest heaters I could find in the aquarium stores, I do not recall the wattage, but it was quite a jump from the wattage ratings of the smaller ones. I think your problem is with the internal thermostat. If you cannot get the adjustment to go high enough, you could open it up and modify the metal strip of the thermostat to cause it to stay on longer. But check for the circulation problem first. You don't want to cook the etchant near the heater just to get the rest of it warm. Hope this information is helpful. MP
  11. I usually rinse the boards and components with water, too. But watch out that you get any detergent completely off, if you use it. If left on the electronics, it could attract dust accumulation, which can cause arcing and shorts later on down the road. Also, a little compressed air will help dry out the water that stays under the chips. Otherwise, you could need a few days of drying time. MP
  12. A lot of the toy companies are using fiber optics to transmit light. It is not the same as communications. They need no precision. Just needs the light to transmit through the fiber optic to the other end. MP EDIT: meaning visible light for visual effects
  13. There is a Buy/Sell forum on this site. It is here: http://www.electronics-lab.com/forum/index.php?board=25.0 MP
  14. The larger aquarium heaters will get hotter than this. I have actually had to watch out for going too hot in my tank. You do not want to heat up the mixture too much. Everything metal in the room will begin to rust....it is also not good to breath this. Your 32C heater is not real hot, but it is still hot enough to make the etching much faster. The other part of the equation is the aeration. The combination of a bubbler and a little heat makes a big difference. MP
  15. Your circuit determines how much curent draw you will have. Not the power adapter. The rating on the power adapter tells you the maximum value that is possible. If I have understood your post correctly, you have no problem. If the power adapter is capable of more than the rating of the transformer, this is ok. You need no limitations in such a scenario. The circuit will only use what it needs. If you want to calculate this, you go through the spec sheets of all the parts, list their maximum current requirements, and add up all the branches of your circuit. MP
  16. If you have a 500 ma current limit in a circuit, you cannot use 1.3A. A resistor can limit current. You just calculate Voltage / Resistance to get the current in Amps. Did you mean the buzzer has a 500 ma current limit? The current for the buzzer is going through T1. Where in the circuit are you concerned about the 500 ma current limit? MP
  17. lupe, A bypass cap on the supply to the voltmeter and/or a bypass capacitor on the input work well. I.m not sure how you layed this out in your design, but some bypass in one or both of these places should smooth out the voltage fluctuations. Use an electrolytic or tantalum polarized as a bypass to ground. Try something in the 4 to 10 uf range to see if this is enough. A 0.1 uf tantalum will also help if there are some high frequencies riding on the voltage. The fluctuations in the meter are caused by variations or spiking in the voltage. The voltage on automotive systems is very noisy. If you have a scope, you can usually see some noise on the DC supply. MP
  18. You don't need a lot of separation between digital and analog parts. This is why they have different ground routings. Treat the two ground symbols as two different connections, then connect them together at one single point at the chassis. The triangle symbol is normally used as a digital ground and the symbol with the lines signifies chassis cround. I have seen many agencies use these differently. Ampeg used the triangle to denote the 1/2 VCC reference on some of their designs whereas the ground with lines was the actual ground. Of course, yours are both grounds and need to be connected at one point. MP
  19. What part of this is controlled by the Hall effect sensor? Is it the automatic clutching part? It would be good if you could get a schematic. If not, you can put a voltmeter across the input and output to see what voltage drop you have between engaged and not engaged. This will tell you if it is being used as a basic on-off switch. It will also help you determine the loss for both positions. MP
  20. Yeah, but sony has filtering inside the speakers. John might not even have a problem. Without specifications, it is a coin toss. MP
  21. Hi Greg, First, you would use any temperature sensor that you desire, put it in a sealed container that will allow temperature transfer, and convert this reading to a 0-5 volt reading for the range of the sensor. A micro with on-board Analog to Digital converter will convert your voltage into a digital number. A little calculation and you can turn on a bit on another pin to control a relay. The pin should use a transistor to activate a relay or you can use a solid state relay. A solid state relay would be better since it has no contacts to wear out, but they are a little more expensive. Another nice feature of using a micro is that you can add an LCD display to monitor the temperature and/or send a signal to the serial port of your computer. MP
  22. dermotcaf, What are you trying to accomplish with this design? How much resolution do you need? Sometimes things are possible but not the best way to go about it. Why not describe your project and let several members of this forum kick out their ideas. MP
  23. Shahriar, The specifications of the speaker are part of it. However, the design of the box is also very important. Also, it must work well with the signal you are putting into it. All of this is calculated into the design by the system professional. You might want to start from a kit as Sasi has mentioned. Otherwise, you should spend considerable time researching this subject. There are tutorials and books that can help you. Kits are a great hands-on tutorial, and many kits will give you a lot of background data that tells you how the specifications were calculated. MP
  24. I didn't see the original conversation, but don't all of the SONY Satellite speakers already have frequency compensation and crossover networks built into them? Why would additional filtering be needed? MP
  • Create New...