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Everything posted by mettula

  1. wow good software - thanks but please can you tell me the mathematical formula to calculate all inductance etcc.... thanks
  2. Hello all, me again I wish to know what is the formula to calculate the length and the diameter of an aircore inductor when you have only the inductance value. i.e. for example how to calcultate the diameter and length and turns of an inductor of inductance .15uH thanks very much
  3. and yet another question which i cannot make my mind about. what circuit produces a sine, square, triangular, and saw tooth waveforms opamps or oscillators? i mean oscillators can be build from opamps. what is the best answer to that thanks
  4. am sry is the output going to be +20V. because 5 x (1+[36k/12k]) but as the suply voltage is=/- 18V. will there be clipping ??
  5. if the supply voltage of a non inverting opamp is +/- 18V, the input is 5V sinosodial wave. Ri = 12k, Rf = 36k. what is the output? is the output going to be 15v?
  6. Hello all, I need some help with this question Which of the following statements is not true and why? a. An oscillator must have a source of energy. b. An oscillator must have a frequency determining circuit. c. An oscillator must have an amplifier. d. An oscillator must have a negative feedback circuit. Is it b the one which is not right? thanks a lot
  7. Hello - I need a formula for how to calculate the frequency of a third-order low pass filter containing an inductor and 2 capacitors (pi filter) plz
  8. Hello, plwease can anyone tell me how to calculate (mathematical equations) the cutoff frequency of a pi - filter and a T - filter. thanks very much for your help and patience
  9. well I made the expression using Karnaugh mapps and the resultant expression is quite long because of the nature of the posibilities. hope it helps mettula
  10. Hello; I have a quest about transformrs. I wish to know 3 main materials which are used to make the core of a normal (not centre tapped) transformers for 50Hz range to step down 230V into 24V. The transformer is 5VA. Are these 3 materials that can be used ; silicon steel, nickel iron and cobalt iron? or I am in the worng track (as usual :-[ :'( ) Thanks for your help and patience
  11. No you did not get my question again. I am trying to make a half adder with NOR gates. My quest is why when I am arraganging the formula from back to front the result would be different.
  12. no my question was, why when interpreting the circuit in NOR gates, if you make the fomrula the other way round it just woud not work.
  13. hello guys, I have a question on digtal stuff, Why is this happening to me, when I impliment the half adder in NOR Gates if I do it int as int the upper formula in the .jpg, the result is different if i do it as in the bottom formula. Both the 1'st formulas mean the same but the outbuts are different. can someone explain please???
  14. ok thanks - and is b) 2V?? thanks
  15. hello - i have a question to ask; A pulse waveform has a mark:space ratio of 1:4. The pulse duration is 0.5ms and the peak amplitude of the waveform is +10V Calculate - a) the pulse repetition frequency and b) the average voltage of the waveform. ----------------------------- Is the pulse waveform a square wave? If so is the answer to question a) is 0.4Hz And b) 2V ??? thanks for your help
  16. I think I made my point not clear, I wanted to know if the output of the apamp would be connected to the -ive input of the opamp without any resistor, and the positive input of the opamp alsoi without a resistor working at line level, will the opamp work coorectly and with 0 gain??
  17. hi again, If i do not do the feedback resistor and the resistor on the input, whislt working with OPA134 and the input being at line level, will the IC have 0 gain? or will it just wont work??
  18. can you suggest than a more professional opamp if you please.....
  19. ok thanksa audio guru - but another questions; 1) which you think is of best quality, a balun transformer or an opamp? 2) about the opamp which you think is best? tl 071?? thanks
  20. Audioguru, can you post me a circuit or help me visualize a circuit of the balancing op-amp please. Is it putting the input through an inverting opamp of 0 gain, and than putting the output to pin 3 of the xlr?
  21. Hi all, sry for asking again, but can anyone tell me how can I convert an unbalanced signal to balanced signal. Do I need a BALUN transformer? or just a centre tapped transformer?? can anyone also suggest a brand of such items??? Thanks very much matthew
  22. thanks audioguru. I'll try it; maybe it'll melt down knowing my luck!! lol but very thanks for evrything I appreciate your patience and help Mettula
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