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  1. walid1

    Audioguru FM Tx

    I'm sure u OK but: 1) tell me where the error in my calculations 2) What was the first the circuit with its resistors value known, or the whole circuit is not known. I mean when you finished the 1st stage and move to this VCO stage, you sure put your assumptions, is VE=2.25 is one of them then u...
  2. walid1

    BJT biasing formulas

    To AUTIr Autir:"why did you choose a ratio of 10" I think that there is a rule: If you want a voltage gain say 100 don't make one stage to avoid distortion, make it two stages (10 * 10) or if you can more.
  3. walid1

    Audioguru FM Tx

    Hi all my friends Audioguru said: "4) I made the mic preamp sensitive enough to pickup sounds in a room. Try 5mV as its output (I didn't measure it) and the transmitter should have full modulation of 75kHz." Walid: Two questions needing direct answers 1) How u made the mic preamp sensitive...
  4. walid1

    C-E Amp circuit sim using spice

    Hi all 1) I don't understand what prateek mean! 2) thank you Audioguru for your interest though I don't know what the lettet you whant to receive me? 3) all those replys are out of my question. yours, walid 
  5. walid1

    Audioguru FM Tx

    All the time I ask one question and with your reply it become 100000 questions, I don't know why. Other friends in this community just look leaving me alone with you, also i don't know whyyyyyyyyyy!!! In your last reply You said: Audioguru:"a)The emitter voltage is 2.25V (a guess)." Walid: I...
  6. walid1

    C-E Amp circuit sim using spice

    What do you want?
  7. walid1

    Audioguru FM Tx

    I forgot 2 things (1) is Vcc to the 1st stage is 5V after the regulator (2) Why C2 it is strange, may be negative feedback! thanks
  8. walid1

    Audioguru FM Tx

    Hi all my friends, I write these commands for Pspice sim.: Audioguru FM Tx 1st stage (Audio preamp), V- divider configuration VCC 1 0 5V Vmic 8 0 SIN( 0 XXX XXX 0 0 0 ) Rmic 8 7 XXX R2 1 2 150K R3 2 0 39K Q1 3 2 4 2N3804 R4 1 3 10K R5 4 0 470 RL 6 0 XXX C1 7 2 330N C2 2 4 100P C3 3 6 330N C4 4...
  9. walid1

    BJT biasing formulas

    Hi AUDIOGURU Audioguru:"The 1st thing was to choose a voltage gain of 10" Walid: Voltage gain Av = Vo/Vin, how this affect my calculations of resistors, tell me please. Audioguru:"so leave the collector resistor as 10k." Walid:" Why you insistent to take it 10K, 8.2K is a close value to not to...
  10. walid1

    Audioguru FM Tx

    To Alun, I mean it, I want all the readers and you to see and share the discussion with Mr. Audioguru.    To Mr. Audioguru: Audioguru: "Do you have questions about it?" Walid: Sure I have, I have a dozen of questions, lets start: FM Tx is one of the important subjects that interests me and...
  11. walid1

    BJT biasing formulas

    Hi my best friend Alun, I'm never ignore your replies, I read it carefully every time and I'm waiting for your next instalment that you will add Re in it to the previous common emitter amp and then finally the resistor below the base and you will explain everything, I wait for this tell now. The...
  12. walid1

    monostable and astable...

    Look at this site: http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/flipflop.html
  13. walid1

    Audioguru FM Tx

    Dear Audioguru, please can you lell me where can I find a full text about your FM Tx whose circuit is attached below. thank you.
  14. walid1

    C-E Amp circuit sim using spice

    I write the following prog to simulate the circuit shown in Fig.C-E below: common E Amp freq response VCC 7 0 DC 12 VS 1 0 AC 1 Q1 4 3 5 Q_2N2222A_N RS 1 2 1K C1 2 3 2uF R1 3 0 10K R2 7 3 30K RC 7 4 4.3K RE 5 0 1.3K C3 5 0 10uF C2 4 6 0.1uF R3 6 0 100K .MODEL Q_2N2222A_N NPN( IS=11.9F NF=1 NR=1...
  15. walid1

    BJT biasing formulas

    Dear Audioguru I take 4 peices of paper, write every hard aspect u tell me in a descrete papare. then I read all this document from the beginning, when reach a hard point i look to the related paper, finally i understand many points (but not all) and i descover that u are a genius, yes you are...
  16. walid1

    BJT biasing formulas

    Hi all my friends in this community especially Audioguru I'm sorry for the many mistakes in my last reply. Audioguru is true I'm false (1) hfe is 230 and not 20.3 as i do, because it is 0.55m/2.4u and not 0.55m/027u (2) I mean a fixed bias and not a self-bias sorry I'm confused (3) All other...
  17. walid1

    BJT biasing formulas

    Hi autir Audioguru's design not a holy, there are many schools in designing a transistor amplifier. One of the simplest ways you can found in this site: http://www.electronics-tutorials.com/amplifiers/small-signal-amplifiers.htm it is very good for you to understand what you want, read it...
  18. walid1

    C-E Amp circuit sim using spice

    I write the following prog to simulate the circuit shown in Fig.C-E below: common E Amp freq response VCC 7 0 DC 12 VS 1 0 AC 1 Q1 4 3 5 Q_2N2222A_N RS 1 2 1K C1 2 3 2uF R1 3 0 10K R2 7 3 30K RC 7 4 4.3K RE 5 0 1.3K C3 5 0 10uF C2 4 6 0.1uF R3 6 0 100K .MODEL Q_2N2222A_N NPN( IS=11.9F NF=1 NR=1...
  19. walid1

    Hi gentlemans I need help you...

    Clear, he is student and his teacher asking him for a project and he want many idias to cgoose one. Alun understand this and directed him to our Project Index thats all is it clear ECET0purdue thanks
  20. walid1

    12 volt battery charger

    The following answer from Ante is very very very good: ""If you put a smoothing cap after the rectifier you will sabotage the function of this circuit. The circuit uses the half cycles (pulsing DC) to make it possible for the SCR to turn off, if it didn’t turn off each half cycle there would be...
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