Search results

  1. T

    $2 Ring Modulator

    Do a search for ring modulators. There are many hits. Here is another video. http://video.search.yahoo.com/search/video?p=ring+modulator
  2. T

    improving cellphone signal strength

    Radio frequency circuits are very complex and difficult to build. If you want to learn, you could buy a ARRL Handbook. The first cell phones were built by amateurs. I can remember when hams had 2 meter radios and repeaters, way before cell phones came out. American Radio Relay League
  3. T

    Microphone doesn't work but standard output audio works

    Maybe you could build or buy an audio amplifier. Maybe a CB power mike would work.
  4. T

    Analoge audio router.

    I think two single pole rotary switches would do the job. Hook all the outputs to one switch and hook all the inputs to another switch. Hook the two wipers together. Now you can hook any output to any input. You probably will want break before make switches. Jameco only has 12 positions...
  5. T

    Experiment 9; MAKE: Electronics

    I think that your experiment is working properly. The problem is that your RC time constant is too short for you to see it charge up. Try using larger resistors, like a 5k ohm. Resistance times capacitance equals Time. RC=T. This is the time it takes for a capacitor to reach 63.2% of a full...
  6. T

    Backup System

    You've got it hooked up right. All you need now is some solar panels and a solar panel voltage regulator. :)
  7. T

    556 dual timing circuits trouble

    Try removing the 4.7k resistor and place a .01 capacitor on the trigger to ground. I believe that I've had more trouble with 555s than any other circuit. I still have some 555n that I can't get to work properly.
  8. T

    Help with voltage controlled switch

    What was I thinking? You are right. The 8v zenner would only keep the voltage from going higher not lower. :o
  9. T

    DOORBELL circuit / project

    What circuit are you using? This is the formula, Resistance times capacitance equals time in seconds, one divided by seconds equals frequency. 1/RC=frequency Example 10k ohms times .1 microfareds= .001 second. 1 divided by x or .001= 1000 Hz. A sine wave generator might give a more pleasant...
  10. T

    Connecting a power supply and battery in paralell

    Every car I have ever owned has the voltage set a 13.8. But what do the car manufacturers know?
  11. T

    Help with voltage controlled switch

    A 8 volt zener would stop the op amp from working. It would have to be lower than the other zener.
  12. T

    autoprotected mosfet

    Looks like your driver at 4 amps, puts out almost as much as the final mosfet at 5amps. I don't understand the charts, Turn off Drain-Source Voltage Slope. On the vertical side, it says V/us (does this mean voltage divided by micro seconds?) at 200ohms it is a little over 160 at 800ohms it...
  13. T

    Help with voltage controlled switch

    That's a nice circuit, but I would make a couple of changes. From my playing around with mosfets, I found out that they won't turn on completely in a voltage follower circuit. I would recommend putting the load on the drain and ground the source. Also if the mosfet shorts it will overload the...
  14. T

    Electronic Simulation Software

    Thanks a lot for Circuit Maker link! I finally got it to work and I spent a few hours today learning how to use it.
  15. T

    Help to Design EGR Valve Simulator- Cheater

    Wow, that's great!
  16. T

    DC-DC Converter Design

    That schematic is too small for me to see. Is there any way I can make it bigger? When I change the zoom on my computer, it gets smaller! What are you going to use the 180 volts for?
  17. T

    Huge trouble driving a stepper motor with an h-bridge

    gate resistors I noticed that you have no gate return resistors on the N channel mosfets. http://www.cadvision.com/blanchas/hexfet/np-s.htm
  18. T

    Watch project for the blind

    Why reinvent the wheel? They already have watches and cellphones that speak the time.
  19. T

    I am trying to save on my electric bill

    Going totally off grid is not a good idea. You will have to spend a lot of money buying batteries, and believe me, you will spend a lot of time maintaining those batteries. Don't ask me how I know! Solar power with a grid tie is the way to go. When you are not using power the meter turns...
  20. T

    Help to Design EGR Valve Simulator- Cheater

    Yeah, maybe he will maybe he won't. Some guys don't want to give away their secrets. I'm always trying to learn something new. Some might say I'm too nosy! But sometimes it pays to be nosy! I'm just curious about how the electronics work on that motor, and see if there is a way to hack the...
Top