Search results

Search Forums New Posts
  1. walid1

    telephone related question #2

    From all of this discussion with Mr. audioguru about make/break ratio i conclude: The make/break ratio is the ratio of the time that rotary dial pulsing makes the phone's connection to the time it breaks the connection. Europe has a different standard than North America. Setting M/B pin either...
  2. 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...
  3. walid1

    want free software

    ThanksAnte this is what I look for thank you very much
  4. walid1

    telephone related question #2

    OK, this is a good answer, what I understood is when I dial number say 3 I hear teck - teck - teck -  which mean that telephone connect and disconnect three times that is M/B = (time of 1 teck) / (time of one -). Now the new question is if I live in USA and M/B ratio there is say 67:33 and I...
  5. walid1

    telephone related question

    Hi Mr. audioguru, I'm coming back, I know I annoying you with my foolish questions but i expect patient, so lets go back to our discussion: Believe me i agree with all your saying, but your answers are not pour directly at what i ask, please tell me directly if true or false and tell me where...
  6. 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"
  7. walid1

    telephone related question

    Hi Mr. audioguru, thank you very much for your response, I agree with you, there are two of the diodes are forward-biased all the time and I'm sure that rectification of the audio doesn't happen, but how??? Let us examine what I think (it may be wrong!). Look at fig.1 if we put a sinusoidal sig...
  8. 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
  9. 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.
  10. 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
  11. 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...
  12. walid1

    Telephone: ELECOM INC. phonerex 9151

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

    Understanding this circuit diagram of AK-700 telephone

    hi i have an extra equestion can anyone tell me about how the signal pass from MIC through C7 to first amplification stage Q4 then passing small part of this signal to speaker through Q5, now how this signal reach the telephone lines to the caller side, how it pass Q2 and what about the...
  14. walid1

    Understanding this circuit diagram of AK-700 telephone

    hi audioguru thank you very much for the useful informations u gave me and i have another questions as: 1- datasheets of hm9102 2- when someone talk near MIC, i think that voice signal  go through C7 to base Q4 then through the power line to the collector of Q2  at this point i cant understand...
  15. 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...
View older results
Top