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Latest posts of: mettula

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 1 Electronics Forums / Theory articles / Re: inductor on: May 31, 2007, 11:32:19 AM wow good software - thanksbut please can you tell me the mathematical formula to calculate all inductance etcc....thanks
 2 Electronics Forums / Theory articles / inductor on: May 28, 2007, 07:14:48 AM Hello all, me againI 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 .15uHthanks very much
 3 Electronics Forums / Theory articles / Re: Oscillator question on: May 20, 2007, 04:13:22 PM Thanks guys.
 4 Electronics Forums / Theory articles / Re: Oscillator question on: May 17, 2007, 01:03:16 PM and yet another question which i cannot make my mind about.what circuit produces a sine, square, triangular, and saw tooth waveformsopamps or oscillators? i mean oscillators can be build from opamps. what is the best answer to thatthanks
 5 Electronics Forums / Theory articles / Re: another question, regarding non inverting op amp on: May 17, 2007, 11:57:05 AM thnks audio guru - i understand now
 6 Electronics Forums / Theory articles / Re: another question, regarding non inverting op amp on: May 17, 2007, 11:24:34 AM 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 ??
 7 Electronics Forums / Theory articles / another question, regarding non inverting op amp on: May 17, 2007, 11:04:08 AM 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?
 8 Electronics Forums / Theory articles / Oscillator question on: May 17, 2007, 06:14:27 AM Hello all, I need some help with this questionWhich 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
 9 Electronics Forums / Theory articles / Re: pi filter on: April 03, 2007, 08:05:47 AM 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
 10 Electronics Forums / Theory articles / pi filter on: March 31, 2007, 08:45:57 PM 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
 11 Electronics Forums / Theory articles / Re: Logic gates question on: February 25, 2007, 02:01:32 PM well I made the expression using Karnaugh mapps and the resultant expression is quite long because of the nature of the posibilities. hope it helpsmettula
 12 Electronics Forums / Theory articles / transformers on: February 25, 2007, 01:09:28 PM 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
 13 Electronics Forums / Theory articles / Re: digital question on: January 19, 2007, 11:17:24 AM 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.
 14 Electronics Forums / Theory articles / Re: digital question on: January 19, 2007, 04:23:00 AM 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.
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