Greetings and please help...

Discussion in 'General Electronics Chat' started by ElectronMan, Jan 29, 2007.

  1. ElectronMan

    Thread Starter New Member

    Jan 29, 2007

    My name is Geoff and this is my first post on this forum. I'm perfectly willing to tell anything about myself but I'll just start by saying that I'm a home owner in NorCal, I'm 30 and I'm facing the possibility of a career change which is the reason I joined this forum. My username isn't even anything special, just something I picked out of the air because I had to.

    I apologize in advance to the moderator, I have many questions to cram into this one post.

    Long story short, I've been in the same field (fire alarm) for nine years right out of Heald College. I have my associates degree in computers/electronics but I freely admit that electronics has never come easy to me. I suspect that many of you on here are better at it on the grounds that it can be a hobby as much as a career, let alone natural talent and whatever else.

    This Friday I'll be taking a written exam for a new job, I have a study guide from the employer and two big electronics books but I need a "tutor." Below will be questions from that study guide that I'm hoping many of you can "dumb down" for me. I appreciate it.

    1) I need to be familiar with Kirchoff's Voltage and Current Laws.
    2) Determine the time constant of an RC Network.
    3) Calculate Reactance, Impedance, and Resonant Frequency.
    4) Relate the characteristics of tuned circuits and state how they affect the operation of filters and oscillators.
    5) What is a tunnel diode, and a signal diode? What are their schematic symbols? What are JFETs, MOSFETs, and IGBTs? What are their symbols? What is an SCR, Diac, Triac? What are their symbols?
    6) I need to (and don't) remember how to use an oscilloscope.

    There's plenty more but I won't get into it, at least not yet. I'm already feeling overwhelmed. As I said I've been in fire alarm for nine years, I've let everything that I might have known that isn't FA related leak out my ears.

    Thanks again!

  2. hgmjr

    Retired Moderator

    Jan 28, 2005
    That is a lot of information to master between now and Friday.

    I can recommend that you take a look at the material contained in the AAC tutorial at since it can get you passed the basics. Your questions 1, 2, 3, and 4 will be covered by the material.

    You can find out information on Q5 and Q6 by googling the topics.

    Since you are looking to change careers, then you have ample motivation to refamiliarize yourself with electronics however much time that takes.

    If you don't obtain the job for which the test is being given, at least you can get things started off toward re-learning the material you will need for the next job opportunity that comes you way.

    Please let us know what we in the forum can do to clarify any of the material that is confusing.

    Good Luck,
  3. Dave

    Retired Moderator

    Nov 17, 2003
    Hi Geoff and Welcome to All About Circuits!

    Have you looked at our on-line e-book? Many of the things you will need to look at are covered in this textbook, and are explained in a simple and concise manner.

    Try: Volume I - Chapter 6

    Try: Volume V - Chapter 1.7

    For reactance and impedance, try: Volume II - Chapter 5

    For resonance, try: Volume II - Chapter 6

    For filters, try: Volume II - Chapter 8

    For oscillators, again try: Volume II - Chapter 6

    Tunnel diode
    Signal diode is a type of standard diode that passes low currents, typically less than 100mA
    JFET: Junction Field Effect Transistor
    MOSFET: Metal Oxide Semiconductor Field Effect Transistor
    IGBT: Insulated Gate Bipolar Transistor
    SCR: Silicon Controlled Rectifier

    Circuit Symbols, try: Volume V - Chapter 9

    We don't have any information at this point about using an oscilloscope. We do have information for other test equipment. If you ask any specifics here in the forums someone will be able to give you some guidance.

    Good Luck.