Search results

  1. walid1

    questions about FM Superhetrodyne Receiver

    Hello Q1) If the received signal frequency = 100 MHz, then the local oscillator equal 110.7 or 89.3 MHz? thanks
  2. walid1

    Transistor collector current

    Hello everyone We all know that Input Impedance decreased when we choose a high collector current, and that is ok I want to ask: When one choose high current? thank you
  3. walid1

    question about Low Pass Filter

    Hi for the LPF shown below, the cuoff frequency is at -3dB or -6dB and why? thanks
  4. walid1

    Electrolytic Capacitor

    Hi Why an Electrolytic Capacitor explode when connected in reverse mannar? thank you
  5. walid1

    about RX-3 IC

    Hello frome the datasheet of RX-3 i get the following application circuit and at the left side there is antenna and related component: My question is what the purpose of the transistor Q1? thank you
  6. walid1

    bad results in multisim 10

    hi I use a multisim-10 to simulate a VCO which intended for 106MHz freq output but the o/p is only 50 KHz as seen in the attached pic why?? thank you in advance
  7. walid1

    What the value of Zout???

    Hello guys The attached photo is a crystal oscillator it is a voltage divider config. but replacing the RC with LC tuning tank I need to know the out put impedance Zout?? Is it XC// XL at the operation freq 27MHz??? please help me thank you in advance http://NOTE: sorry L= 3.48 uH not 1.2 uH as...
  8. walid1

    Where the Archive ????

    We have discussed several subjects did not find an old Please help
  9. walid1

    Pi filter for impedance matching

    Hellow, I build the following pi filter to match 100 ohm source to 1000 ohm load, I did the calculations based on RF Circuit Design Book As u can see at the center freq fc = 30MHz & Q=15 I had 3.771dB, I was surprised by where this value? this is amplification!!!! The second question is...
  10. walid1

    ::) Electronic magazine for you

    I submit this electronic magazine as a gift to the best forum in the world http://www8.rapidupload.com/d.php?file=dl&filepath=39239
  11. walid1

    Automatic heat detector

    Hi I found this circuit Saved in my PC (pdf formatt) and I do not know of any site obtained. This part is what concerns me now This part does not really care because I will focus on how to use transistor as heat detector. The writer wrote the following passage : My question: Is this talk...
  12. walid1

    Questions in Radio receivers?????

    Hi all These days I read a book on radio receivers from the site : http://www.mikroe.com/en/books/rrbook/rrbook.htm During the reading, sometimes I find it difficult to understand some of the points, so I ask you to help me understand. Thank you very much. Question #001 (from sec: 3.1.4...
  13. walid1

    need a program to simulate in electronics

    Hi please I want the program to simulate in electronics to perform some tests on the transmitter and receiver thanks
  14. walid1

    AM reciever mixer

    Hi the folloing fig is the front end of a simple AM radio reciver It contains the AM ferrite antenna and two variable caps, one connected // to the primary coil of the antenna and the other // to the primary coil of the red (local oscillator) transformer. AM sig freq from 530 KHZ to about...
  15. walid1

    Frequency response for a transistor amp.

    Finally, after a long discussion with Mr. Audioguru, i discover that the frequency response is a relation (curve) of freq vs voltage gain (Av). The following Fig is the 1st stage of guru's FM Tx: Av = RC/re, this is assumed at very high freq that makes Xc4 = 0 so shortened the RE But at audio...
  16. walid1

    What happen when downloading the previous stage?

    hi Today, I sat thinking at this point, what happens when the i/p impedance for the subsequent stage is less than the o/p impedance of the past stage? Please clarify the idea Thank you
  17. walid1

    Ft of the transistor

    Hi Ft is the freq at which beta (hfe) = approx 1 for 2N3904 transistor I found that at 300MHz, hfe = 1 frome the same datasheets i found the following curve: look at the red curve at 300MHz, hfe = 5 dB 20 log (hfe) = 5 hfe = 1.8 Now at FM freq (say 100 MHz) and from the red curve, hfe =...
  18. walid1

    A very Urgent Question

    Hi I built a circuit that when a person pass some red led illuminate This signal is connected to a pic to count. The problem is that when that person pass, the led is Intermittent lighting glows irregular and weaken and boosted in a very short time The pic see that several persons How can...
  19. walid1

    MNA question about amplifier

    Hello, Have a look at the amplifier circuit shown I want to know your views about it..... if u find any mistake in it, do point it..... one stage to be mosfet was the requirement, so i have used the mosfet as voltage amplifier and then connected it to the power amplifier...... Thanx for...
  20. walid1

    Salt-taster

    Hi I built this circuit on a test board http://www.redcircuits.com/Page68.htm the sensing leads are simply two thin copper wires i connect these two leads together, this equivalent to a very low resistive solution. when operate the circuit, the red led (D3) is on and the other green and yellow...
Top