Needing help with a circuit

Discussion in 'The Projects Forum' started by ZorAxe, Oct 20, 2014.

  1. ZorAxe

    Thread Starter New Member

    Oct 20, 2014
    Howzit guys,

    I need some help. I have a good understanding for electrician. I know what caps, transistors, resistors all do, but not sure how they all work together in a circuit. I have this circuits and all the components, but I need to understand how it works and why it works so that I can explain it to my cousin. I'm helping him with a school project. It's a simple buzzer circuit and I wanna be able to explain to him how it works. I basically want to understand what all the components do in order to obtain the buzzing sound.

    Any help will be greatly appreciated
    Thanks guys
  2. MaxHeadRoom


    Jul 18, 2013
    A simple amplifier using a NPN and PNP transitor circuit with positive feedback causing the oscillations.
    It is the Electronic version of acoustic feedback of a mic and amplifier in a enclosed space such as a hall where the spkr to mic feedback causes a loud high frequency sound in the spkr = positive feedback.
    The .047uf and 120 ohm resistor is the feedback path.
    Also just look up NPN and PNP transistor technology and function.
    Last edited: Oct 20, 2014
  3. MrChips


    Oct 2, 2009
    Here is an even simpler circuit: