Search results

  1. A

    Why is so hard to mimic the Knight Rider scanner Effect?

    If you use the zoom tool you can see it clearly. Here is GIF version. I added a screen capture small AVI file of the simulated led movement. It looks a bit jerky because I think my PC is running out of computing speed running the simulation and the capture software but it will give some idea...
  2. A

    Why is so hard to mimic the Knight Rider scanner Effect?

    Here is my digital design that includes the smearing effect. The pot sets the sweep rate. I have not tested the circuit in real life but it simulates well.
  3. A

    Why is so hard to mimic the Knight Rider scanner Effect?

    You can create the optical illusion of smearing by using dither with the leds. This can be done in analog or digital
  4. A

    building a generator

    It works because of the residual magnetism remaining in the motor without the need for any external excitation.
  5. A

    building a generator

    If you take an induction motor and drive it faster than it synchronous speed it becomes a generator or also called a "asynchronous generator" To use this as a generator without any external AC source you need something to supply the reactive power. This can be done by capacitive loading.
  6. A

    fm transmitter scematic required

    I must agree with you that I have never seen any worthwhile specifications published by Ramsey on their transmitters! Maybe because the final outcome relies on the builder builing it correct. But then they can do it for the export- fully assembled models.
  7. A

    fm transmitter scematic required

    Have you tried any of the other stock names like Ramsey before?
  8. A

    fm transmitter scematic required

    Sounds very promising. Please report again once you finished testing with your new antenna. BTW what other transmitters can you compare the unit against? Can you say which types you tried out before?
  9. A

    fm transmitter scematic required

    Was wondering if you could give us a report when you receive this transmitter?
  10. A

    Newbie needs help with a project

    Here is a modification to prevent the on-time from exceeding the clock period if the clock rate is made faster. This will prevent 2 injectors to be on at the same time.
  11. A

    Newbie needs help with a project

    Here is your basic circuit. R4 adjust the firing rate per minute. R2 adjust the time the pulse will be high. The pulse out will drive a FET to switch the injectors. R5 will determine the minimum on time of the pulse. R6 will set the maximum clock rate. From the pictures: top trace is clock...
  12. A

    Newbie needs help with a project

    Use a 4 stage counter driven by a clock. Use the counter outputs to trigger 4 separate monostables. The time constant from the monostable can be varied with a pot. Each monostable can fire a power fet to switch the injectors. The clock could also be varied with a pot. This is the idea, now...
  13. A

    OVER-/UNDER-VOLTAGE PROTECTION CIRCUIT ANALYSIS

    Those values are not critical. As long as you get the same adjustment voltage range on the pot without too much current through the pot you will be ok. You should always pick your values to have very little dissipation in the pot by limiting the current flow through the slider. I just noticed...
  14. A

    OVER-/UNDER-VOLTAGE PROTECTION CIRCUIT ANALYSIS

    You would expect the output of the opamp under ideal conditions to switch between supply and GND. Using a rail-to-rail opamp will bring you close to this. Older opamps can't switch like this. So if the low of your opamp switch to 0.4V the transistor may not be completely off. If the transistor...
  15. A

    OVER-/UNDER-VOLTAGE PROTECTION CIRCUIT ANALYSIS

    The 1k resistors are to make sure enough current is available into the base to saturate T1. The diode is added because the opamp is not a rail-to-rail opamp and may not switch low enough to completely turn off T1. The added drop over D5 gives more switch off margin.
  16. A

    v/f control of 3-phase Induction motor

    There are many chips available for this application. They will include all the special features like start boost, braking, reverse etc. which will be complex doing it with analog methods.
  17. A

    want to convert preamp from VHF 2 FM

    Analyzing something like this normally involves smith charts and lots of complicated calculations. It may be difficult for someone to fully explore on this board.
  18. A

    fm transmitter scematic required

    I stumbled onto the EDM page while looking for info on the BH chips. I never bought one as I made my own circuit with a BH1417. I looked at their mod meter at one stage and was thinking of getting one but found a surplus meter on ebay. I have seen a lot of post on the EDM transmitter on various...
  19. A

    fm transmitter scematic required

    The output of the Micromitter without the attenuator will be about 0.1mW and not 10mW
  20. A

    NEED HELP IN A BAD WAY.... LED PROJECT

    You can do it many ways, some less elegant than others.
View older results
Top