Search results

  1. Hero999

    Switching Using a PSU based on temperature

    One of the resistors could be replaced with a potentiometer to adjust the temperature threshold.
  2. Hero999

    Switching Using a PSU based on temperature

    Thermocouples are accurate but not simple to use. I'd recommend a simple thermistor. You don't need a micro-controller, a simple comparator and relay will do. http://www.silicontronics.com/index.php?action=ezportal;sa=page;p=17
  3. Hero999

    Anyone here na gumamit na ng RGB LED/White LED for color detection

    Great, it's good that you've returned. I didn't make much effort to respond in case you didn't return: many people don't. English is the main language spoken on this forum. I'm from England myself but there are plenty of people here from all around the world. I know there is a Filipino forum...
  4. Hero999

    Laser Sensor and Counter

    Sorry but that still will not work as you've drawn it, a photo diode should be reverse biased. As you have it shown, current will flow through the LED and both blow it up and the transistor. To use it in photovoltaic mode you need to connect it between the base and emitter. Don't you mean you...
  5. Hero999

    DO NOT ASK THE SAME QUESTION MORE THAN ONCE! It will be deleted!

    Asking the same question more than once does not increase your chance of a helpful response but only reduces it as people get annoyed at having to read the same thing over and over. Seriously, if I asked you the same question three times would your answer be any different the third time round...
  6. Hero999

    Laser Sensor and Counter

    Whilst that would work I think it's a bit overkill. If the transistor is connected up correctly, a high value resistor connected between the base and the output of the NOT gate will provide positive feedback and therefore hysteresis.
  7. Hero999

    Laser Sensor and Counter

    The circuit drawn wrong. The diode is connected backwards so a large current will flow both through it and the transistor's base causing them to both overheat. The emitter is connected to -5V when you probably meant 0V. There's no pull-up resistor on the input, I assume it's a CMOS input so...
  8. Hero999

    cable tv technical adviser

    Is this spam? What's the point of the poll? Loads of people could respond yes or no and you still wouldn't receive any help. Even if I knew someone, I wouldn't give their number or email to a stranger on the Internet. You've missed the whole point of a forum. The idea of an Internet forum is...
  9. Hero999

    Brightest LEDs on the planet?

    An SMPs can be made using fairly common components. The first shows how it can be done using diecrete components and the second shows a comparator. If a comparator with a push-pull output is used Q1, D1 R4 and R5 can be eliminated.
  10. Hero999

    AC power outlet

    I mean anyone who says batteries are a higher quality voltage source than a linear regulator are talking rubbish. Some audiophiles believe all sorts of rubbish ranging from scratchy old valve amplifiers sounding better than solid state amplifiers to gold plated oxygen free mains cable being...
  11. Hero999

    AC power outlet

    Sorry buy that's total nonsense. A battery will have a much higher impedance than a linear regulator. A good amplifier will also have a high power supply rejection ratio so even if the power supply is noisy it won't make any difference. The only time when noise can be a problem is when it's...
  12. Hero999

    circuit distortion

    So you think more transistors must mean more distortion? Here's an example of a circuit which proves your theory to be wrong. In the first circuit there's three separate stages of voltage amplification, Q1 and Q2 just provide current amplification to drive R4, Q3 & Q4, Q6 & Q7, are...
  13. Hero999

    AC power outlet

    1) It shouldn't be. 2) That depends on the power supply, a regulated power supply is much better than a battery.
  14. Hero999

    Please recommend a Good Electronics Book

    The Art of Electronics is still a good book, believe it or not the basic principles haven't changed in the last 20 years.
  15. Hero999

    7805 and AC-Adapter

    I'd recommend using a 1.5A transformer in a 1A regulator circuit. The next question will probably be: "I've built the circuit using a 6VAC adaptor but the output voltage drops when a 1A load is connected. What's wrong?"
  16. Hero999

    Cross Reference for PCR 606J

    Let me guess, it's a set of Christmas tree lights? Any TO-92 SCR with an adequate voltage rating will probably do but be careful with the pin-out. It might be a good idea to check the pin-out for the one that works before getting a replacement. I have some old Christmas tree lights I'm...
  17. Hero999

    7805 and AC-Adapter

    Sorry but if you need to ask this then you probably need to do some more learning before you build your own regulator circuit. I suggest doing a bit more research.
  18. Hero999

    Need A Help Circuit Diagram "Power Saver Supply"

    Sorry, your post doesn't make any sense. Please tell us exactly what you are trying to do?
  19. Hero999

    Help me >>>Circuit Diagram for 12vdc inverted to 220vac generate sinewave

    No one's going to design the whole thing for you. I'll give you an idea as to the basic building blocks and you can go away and research them. A pure sinewave inverter has three main components: a sinwave gennerator, DC-DC converter and a class D amplier. The 12VDC is boosted to just above...
  20. Hero999

    220 to 110 V convertor advice

    It's an autotransformer. It has three connections, primary, secondary and neutral. Both the neutral for the input and output connect to the neutral. http://en.wikipedia.org/wiki/Autotransformer The only trouble is you need to identify the different windings. My guess is that the middle is...
Top