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  1. Arouse1973

    Help needed, equivalent resistance of this circuit

    A quick method to get a very close answer is to remove the middle resistor 3R then solve as normal. The middle resistor can be removed because it has virtually the same voltage between its two terminals to within 16mV. This then becomes 8.7R. Thanks Adam
  2. Arouse1973

    SMPS's with cascoded opto feedback

    I think your right, an emitter follower configuration will be faster because the miller capacitance for a common emitter version is CM = Cbc*(AV+1). So because the common emitter version has voltage gain greater than 1 this will magnify the capacitance and the dominant miller capacitance will...
  3. Arouse1973

    What exactly Is voltage drop and how Is It detected?

    Because you have put the voltmeter across the resistor the internal resistance of the voltmeter will effectively reduce the value of the resistor ever so slightly. And you will have two paths for current. One through the resistor and one through the meter. The voltage meter will have on it's...
  4. Arouse1973

    Help Needed with SCR and Optocoupler

    Hi Kris I think the trigger needs to be negative. And yes I meant small and large windings exchanged. Thanks Adam
  5. Arouse1973

    What exactly Is voltage drop and how Is It detected?

    Does it make it clearer if I said to move between point A and B 1C needs 1J of energy in an electric field of 1V. I assumed you would realise it was from start point flowing to end point. Adam
  6. Arouse1973

    What exactly Is voltage drop and how Is It detected?

    For anything to move it has to gain energy even electrons, what happens to this energy is dependant on what it passes through. To move an amont of charge in a circuit it has to get energy from say a battery. So a battery of 1V producing a current of 1A will have to gain 1 joule of energy. If...
  7. Arouse1973

    Yagi-Uda antenna 2100MHz

    Too strong a signal can cause issues, might need an atenuator,just a thought. Adam
  8. Arouse1973

    What exactly Is voltage drop and how Is It detected?

    I tend to use the term potential difference and not voltage drop. For instance when a current passes through a resistor it will develop a potential difference across that resistor. This is what you call voltage drop. It is the difference in voltage between two points. Voltage is not energy...
  9. Arouse1973

    Help Needed with SCR and Optocoupler

    I know it might be a silly question but make sure you have the transformer connected correctly. Also it would be nice to see a bleed resistor across those capacitors in case the mains is unplugged at it's peak remember the fuse is there to protect the circuitry and wiring from overheating and...
  10. Arouse1973

    i need assistance with LEDs

    This quite a complex project to make it work properly. Have a look at the link below it might give you some ideas. If you want to make something yourself then I would be looking at some kind of filter to allow say bass frequencies through and a transistor amplifier or switch depending if you use...
  11. Arouse1973

    current calculation

    Thank-you Laplace. Yes silly me it should have been. The SI name for charge is the Coulomb and it's unit = C=A*s and it's symbol is Q, q, or e. And an ampere-second (A-s or amp-second) is an amp supplied for one second. Thanks Adam
  12. Arouse1973

    Composite signals...

    No probs Adam
  13. Arouse1973

    Composite signals...

    From what I remember, but I might be wrong is that the composite signal has defined voltage levels for different parts of the waveform. This then tells the receiver all it needs to know about the signal. White level Black level, brightness etc. You have to remember that it will have a 75 Ohm...
  14. Arouse1973

    Understanding resonators

    Hello When you say resonators do you have any particular type in mind? One of the most common resonators is the Crystal oscillator. This is a very small piece of what's called piezo electric material. In the case of common crystals it is quartz.. When you apply an electric field to a...
  15. Arouse1973

    current calculation

    Current is a flow of charge + or -. Now forget the involvement of electrons for the minute as this can confuse matters. When a unit of charge passes a point in time this is called electrical current.. The unit of charge flow is A / s and the unit of electrical charge is the Coulomb, when you...
  16. Arouse1973

    Help identifying cable

    Can you take a closer picture LG my xray visions not working right now. Thanks Adam
  17. Arouse1973

    Indentifying SMD component

    Could it be a 4148 by comchip?. I am using my tablet so a bit restricted. Thanks Adam
  18. Arouse1973

    Indentifying SMD component

    Looks like a diode yes. I'll have a look and see if I can help Adam
  19. Arouse1973

    Large capacitor for power outages?

    Kidding why, some kind of joke on me?
  20. Arouse1973

    Alternative fet driver

    International rectifier do several devices. Thanks Adam-
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