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What are the applications of a transistor

  1. Mar 25, 2012 #1
    Hello! I have done some research on transistors because I want to increase my current via increasing the voltage of a circuit in order to offset the increased load. As far as I understand, transistors can amplify (increase) voltage and current, as well as rectify (does this mean it can convert AC to DC?). Is this true that it will increase the current and voltage? And if so, how can I know by how much it will increase it? And if not, what are any other options for increasing voltage and current when a load is placed on a circuit?
    Thank you!
  2. jcsd
  3. Mar 25, 2012 #2


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    Based on your post I have to wonder if you are going about this the wrong way. Transistors do not really increase anything. They control. The power has to be available to start with and I am not sure you are grasping that.
  4. Mar 25, 2012 #3


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    Transistors cannot generate extra voltage.

    They can control a voltage that you supply to them but this voltage has to come from a power source like a battery or a power supply.

    They are not normally used as rectifiers either. Diodes or packages of diodes called bridge rectifiers are used as rectifiers.

    Could you explain what you are trying to do?
    Last edited: Mar 25, 2012
  5. Mar 25, 2012 #4
    We do have the voltage we want in our circuit before the load is applied. However, once the load is applied, the voltage drops and will not rise back up above a certain voltage (2 Volts). We want the voltage to be at least 4 volts
  6. Mar 25, 2012 #5


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    Where is this voltage coming from?

    Please explain in as much detail as you can.
  7. Mar 25, 2012 #6
    The source of the voltage is a ceramic piezoelectric disc, then the current is passed through a rectifier and converted to DC and stored in a capacitor. I have even gotten the VDC to reach 25 Volts without the load, but when the load is applied the voltage will plato at about 2 volts.
  8. Mar 25, 2012 #7


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    Is this the type of device that is used to light barbeque burners?
    These generate a spark that lights gas for a barbeque.

    Most piezo devices like this have a high impedance so that they can generate a voltage but not much current.
    So, if you put a load on them and try to draw more current, the voltage drops.

    If you want this to be a power source, it won't be a very good one as there is not much power available.

    You could use it to control a transistor, but then you would be using the battery supply for the transistor as your source of power.
  9. Mar 25, 2012 #8
    yes, so i am using the piezo discs as a generator, converting mechanical to electrical energy. But the fact that it is a high impedance circuit is the problem i am facing. What i want to be able to do is maintain a good amount of voltage (at least 4 VDC) even with the load applied. Is there a way that i could increase current or voltage so that the voltage even after the load is applied will be at least 4?
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