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  1. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    If Q1 is going to leak 0.5mA when turned off, the LED will never turn off. What you are saying is absolute RUBBISH.
  2. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    What absolute rubbish. As if Q1 is going to leak 0.5mA when turned off. If this were the case, transistors would never have been successful.
  3. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    The fact is this: Your method of putting an emitter resistor on Q1 fails to turn off the LED. When the base voltage is zero, the transistor is turned OFF and no current flows through the emitter resistor so it does not matter what value of resistance is placed on (in) the emitter, IT WILL HAVE...
  4. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    Ratch, you have completely missed the point of the exercise. Putting an emitter resistor on the first transistor does ABSOLUTELY NOTHING. When input voltage is zero, the voltage between the collector and base will be about 7v and the leakage will be about 10uA. If the gain of the BC557 is 400 to...
  5. C

    Where could I find a low RPM high torque motor?

    You need at least 2HP. The RPM needs to be high and the cutters need to be on a very heavy armature as it takes an enormous amount of energy to cut through plastic and bottles and if you jam up the machine it will take hours to open it up and unblock it. The grill at the bottom determines the...
  6. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    LEAKAGE Here's a problem with LEAKAGE. This is when a very small current flows through a transistor (or any other component) and this current cannot be reduced or stopped. In the following example, Q1 is a leaky transistor. It can be any type of transistor and although the leakage current...
  7. C

    Where could I find a low RPM high torque motor?

    Our shredder (granulator) runs a quite a high RPM.
  8. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    He is obviously trying to turn the LED off when the input to the circuit is 0v. "That means that it will be even easier to get the transistor to turn on the LED." We are trying to turn the LED OFF. You have not reduced the leakage. When the input voltage is 0v, the leakage still exists.
  9. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    The requirement is to remove the 14uA. YOU HAVE NOT DONE THAT. BC557C is 400 to 800 not 125. You have completely dodged the question. You are completely wrong I have written this up on my website under SPOT THE MISTAKE as I cannot believe what I am seeing.
  10. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    When V1 is zero, the collector-base voltage of Q1 will be about 7v and about 14uA will flow and the LED will not be turned off.
  11. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    To get the collector of the first transistor to rise high enough to prevent the second transistor turning on, the emitter resistor will have to be something like 100k. NOW, how are you going to turn ON the first transistor ???????
  12. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    Here is what Ratch is saying: "Right now, with that high base resistance (100 k) in Q1, almost all the Icbo will go through the base-emitter junction of Q1, and get betatized into a much larger current. You should take out Rb, and put in an emitter resistor Re. The emitter resistor will look...
  13. C

    Voltage regulator for LED panel

    If you use 20 strings of 5 LEDs, you will be able to turn down the voltage by removing the 10-turn pot and connecting the three leads of a normal pot to the 3 holes on the PC board. 5 x 3.7 = 18.5v You will be able to adjust the voltage from 17v to 23v with a 220R resistor in each string...
  14. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    "See post #4 of this thread." That doubly-determines Ratch doesn't know what he is talking about.
  15. C

    Soldering Iron Catalyst

    Generally it is Platinum.
  16. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    Forget about what Ratch said. He does not know what he is talking about.
  17. C

    Input to a microcontroller

    The pot and cap are part of a sub-routine that charges the cap via the pot and looks to see when the input is HIGH. From this it will tell you where the wiper is.
  18. C

    HP3478A Bench DMM... Good for a beginner starting out?

    Buy a $10.00 DMM and a $5.00 analogue meter. Read my website and see why I suggest this. Talkingelectronics.com Testing Electronic Components
  19. C

    Determine the Vcbo of a germanium transistor and the voltage drop along the connected components.

    Suppose the leakage is 20uA. The PNP will amplify this say 200 times and the emitter current will be 20 x 200 = 4000uA = 4mA and the LED will turns ON. If you put a 1k resistor on the collector of the first transistor to the positive rail, this current will flow through the resistor and...
  20. C

    Need Help With A Charging System On A Motorcycle. Have Schematic

    The diagram above is incorrect.
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