Jump to content
Electronics-Lab.com Community


  • Posts

  • Joined

  • Last visited


mik3ca's Achievements


Newbie (1/14)



  1. I don't get it. What I want to do is design an 8051 system with 2 JEDEC approved 32K EEPROM modules, and a JEDEC approved 8K SRAM. I want to do it on a single sided board. It seems that the JEDEC approved standard, just does not work with my 80C51 chip. Can anyone tell me why the JEDEC standard assigns certain pins to certain addresses and data on the rom instead of having the data pins all on one side of the chip and other pins address? Membership for JEDEC costs at least $6000 and there is NO way I'm paying $6000 to find out this answer.
  2. It seems that I only get ANY result if the 100K is replaced with a lower value resistor (330 ohms and under). As for blowing the transistor, I don't think I broke it. For the processor, I don't think I broke it either. No matter what I do, the best I get is that 1/2 the data is received correctly, and sometimes the system resets itself and displays screwed-up results. Maybe I'll try 1K, but I don't know if it will work.
  3. Have a look. I was trying to use it with my 8051 microprocessor. If I replace 100K with a short, the circuit 1/2 works (receives correct data) and 1/2 the time, it shuts off, turns back on, and then resets. Would capacitors help? I already have everything on a PCB and do not wish to change the layout.
  4. as for the circuit MP believes to be correct, why are there so many transistors? why not just have two transistors? AND, why are there so little resistors? I think there should be some near the transistors. Its the resistors that limit current and prevent overheating.
  5. It seems that the ONLY way one can make PCB's using an inkjet printer is if multiple copies of the image, perfectly aligned are placed on the board. It appears that printing on the transparency only ONCE does NOT work. I just tried it a few minutes ago on a canon bjc-1000 printer, and as soon as etching was 1/2 complete, I noticed a number of tracks were broken, so broken, that I couldn't even use solder to bridge the connection. The problem with me using multiple copies is the fact that my bloody printer is a GAMBLING MACHINE! 1/2 the time, I can get it to print many copies in the same spot, and 1/2 the time, I can't, and when I can't, then my money goes out the window. I think I will need to buy a laser printer. and if I do, which is the BEST laser printer for the lowest price, and why?
  6. I tried adding resistors, and making it more like talkingelectronics version, but that didn't help. At the moment, my input wires are about 6 inches long, because this section is in the beta stage, and my radio portion works. I want to minimize holding time, in case I pick up sudden changes in the signal. In fact, I would like to pick up some white noise too! Why would I need a photocell to detect a signal? Is there a way to avoid the need of a photocell? (or a diode that behaves like a photocell?)
  7. that was the circuit I was talking about. That circuit barely works for me IF the resistor value is low enough. Sometimes, when I use the diode, the LED just stays on bright, and never dims. So the RC circuit in parallel determine the holding time? What if I were to replace the diode with one that can handle more power like the 1N4007?
  8. I haven't had a transistor blow up in this configuration. Talkingelectronics.com uses a diode in place of my capacitor. I tried that configuration without much success. When the diode is connected this way, doesn't it create a varactor? Which means there is guaranteed capacitance. then I must be on the right track. Because I don't want IC constraints to affect my design. I am going to search for that. Thank you.
  9. I'm trying to make my own VU meter, and I only have partial success. What I would like is full LED from full volume. My LED doesn't dance to the music :( The input is a resistor (which varies the strength) and a capacitor in series. This capacitor is connected to any audio source directly. this circuit uses a 2N4403 PNP and a 2N2222 NPN. The last NPN is used to give the LED a boost. I think I am OK with choosing resistor values, but the capacitor values are trouble. If I choose them too high, then I will have to wait while they charge. How do I choose the correct capacitor values? I am interested in converting normal audible sounds into LED signals.
  10. I'm just wondering, what is the absolute minimum time one would take to etch a 10cm square board if most of it is etch-resisted by the circuit design, and the etch resist is fairly new, never heated, and the board just sits in the etching tank? why do I ask? because I rather let the etching work for me while I do other things than to waste 1/2 hour or more watching a board.
  11. Audioguru stated: Indulis stated: The full post can be found at the following URL: http://www.electronics-lab.com/forum/index.php?topic=8320.0
  12. After reading a post regarding an inductor and an oscilloscope, (somewhere in the project ideas section), It seemed that Audioguru attempted to answer the original poster's question, but then it seems that indulis made post(s) claiming that some or all of Audioguru's answers are wrong. I have found some information from Audioguru to be correct. however, It is always better to learn from someone that is knowledgeable with the subject. So I'm wondering, who is better to learn from and why?
  13. most likely, no. The only way it might help is if a large value one was connected across the ppower supply to smooth out the power voltage, that way, the voltage will be more consistent as the power supply drains. other than that, I cannot see a capacitor as a helpful device.
  14. According to your past equations, It seems that my error rate is at about 6%. Maybe my luck is so bad now a days, that this error rate is making problems for me
  15. oh boy, now I have to go and buy new value resistors. So this must mean that these resistors are hogging the current in such a way, that the outputs from the cmos chip are meaningless. :( According to http://www.electronicproducts.com/ShowPage.asp?SECTION=3700&PRIMID=&FileName=sepana1.sep2003, they state there are two types of R-2R ladders. Current mode, and voltage mode. Which is better for my case and why?
  • Create New...