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  1. walid1

    BJT power supply

    What the difference between: 1- Using one 12VDC power supply connected to RC, and 2- Using two power supplies; +6VDC connected to RC & -6VDC connected to RE, thanks.
  2. walid1

    BJT operating point

    if I have to amplify a sig of 10mV peak (20mV P-P) using a voltage divider common emitter configuration. Power supply is 9VDC. What values of RB1 & RB2 should be to maintain these two conditions: 1- conserve (not waste) the battery. 2- No distortion in the o/p sig. Note: please write the...
  3. walid1

    Very low power FM transmitter discussion

    I'm asking the entire world what I learn from this picture... The picture provided her is from: http://www.rf.fcpages.com/Fm-spy.htm If you go to this page you will find only this picture without any reliable comment. You find similar pages in more than 90% of the web. They only told you that...
  4. walid1

    Hum in the incoming signal

    In Palestinian satellite channel when a signal come to the continuity studio from outside, there is a hum on it (hum in video and audio), and this is clearly obvious when we take the main electric power from our generator, but the internal signals from the studio (cameras and VTRs ....) are very...
  5. walid1

    3dB point or pole

    I read this: "Present-day operational amplifiers are comprised of multiple stages, each of which has a 3dB point or pole associated with it." what the meaning of [a 3dB point or pole]? thanks
  6. walid1

    BASIC FEEDBACK THEORY QUESTION

    I read this: "The ideal parameters are never fully realized but they present a very convenient method for the preliminary analysis of circuitry. So important are these ideal definitions that they are repeated here. The ideal amplifier possesses 1. Infinite gain 2. Infinite input impedance 3...
  7. walid1

    OFFSET NULL ADJUSTMENT

    hi all of you i read this (look at Fig.1) from http://www.uoguelph.ca/~antoon/gadgets/741/741.html but idon't know what is OFFSET null, what the advantages and disadvantages if i care to it or not? thanks.
  8. walid1

    telephone related question #4

    hi, i'm comig back ..... i love you all my question is : All DTMF ICs used in telephone circuits have pin called MUTE (pin 13), in HM9102 IC datasheet i read the following "This output is an inverter normally at low state when there is no key entry. During outdialing it changes to high state...
  9. walid1

    Telephone related question #3

    I have more than 10 telephones schematic diagrams one of them is a very simple {from: circuit ideas} see Fig.1 and I note that all of them use a small signal PNP transistor (T1 in Fig.1 and Fig.2). 1) Why always PNP and not NPN? 2) Why it always connected as a common-base configuration? 3) How...
  10. walid1

    telephone related question #2

    what is make/break ratio, and what these statements mean: "In normal mode pin 10 (of UM9151) is used to select make/break ratio: when i/p = VDD, M/B =1/2 when i/p = VSS, M/B =2/3"
  11. walid1

    want free software

    please some one help me in finding a free software that can help me in studying electonic circuits, i have win95 pentuim1 PC. thanks
  12. walid1

    C_B transistor impedance matching

    i need a theoritical information about designing an impedance matching circuit using a common base transistor configuration. the transistor is PNP small signal type, collectoris i/p and Emitter is o/p. thank you.
  13. walid1

    transistor voltage regulator

    please I need information about how to build a transistor voltage regulator without zener diode i use a small sig PNP transistor like 2N5401 and want to regulate 10 votls DC to 7.5 VDC. please tell me how can i clculate resistor svalues. thanks
  14. walid1

    telephone related question

    any modern telephone has 4 diodes at its input i knowthat these diodes are for polarity protection but voice signals into or out of telephone are pass through these diodes how these signals are affected  are they rectified, i know that they are not rectified  are they carried over a DC level...
  15. walid1

    Telephone: ELECOM INC. phonerex 9151

    please I need a schematic digram of a telephone: ELECOM INC. phonerex 9151 thanks.
  16. walid1

    Understanding this circuit diagram of AK-700 telephone

    hi friends my name is walid from Gaza strip, first of all I am new in this great website and 50% in English language and love passionately electronics. I am interesting in circuit design analysis than build it i think that if u understand u assurance can build so i want to understand the circuit...
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