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  1. M

    Varactor (varicap) FV1043, equivalent in LTSPICE

    Hello, everbody can somebody help me to find equivalent varicap diode of FV1043, i cant find in ltspice FV1043 is for oscillator to change the frequency….. thanks.
  2. M

    FM Ratio Detector is not working

    hi , please can somebody help me about this circuit, is not working i dont get audio signal here is my circuit rename in asc frm txt thanks
  3. M

    FM converter (mixer) -- I don't understand

    Hello, Can somebody help me,to explain me this circuits this is converter, but i realy dont understand how it works( i understand mixers, you put rf to base and local oscillator to emiter, but this is a litlle bit complicated)
  4. M

    Hi, how to make 2 IF from one IF amplifier circuit, to get higher gain

    Hi, i take one If amplifier, from internet and i want to make the second the same, but i dont know how to couple, of what i need to do, to get more gaing can somebody help me? here is one IF amplifier in ltspice, rename in asc, or remove only txt extesion. and what is the best to do, is for fm...
  5. M

    Help with building this transformer in ltspice

    Hi, everything oko_O i just want to tell, can somebody, who have time just to read this file, you understand direct, if you know about fm detection, i just dont know how to make a transformer in ltspice, can somebody told how to make it this circuit with transformer and tuned please
  6. M

    Hello, can somebody check my transistor amplifier schematic?

    Hi, can somebody tell me how to connect some component in this picture, i draw it but is not working because i have no bfg520 transistor, look this picture maybe i make mistake
  7. M

    Hi, has anybody had trouble building the ELENCO 108 AM/FM RADIO KIT

    Hello, i build the radio like they say in the book, and i did everything with VOM(testing with only multimeter), everything was like in book , but when i finish, i switch to am or fm, i just hear high noise :doh:
  8. M

    Hello, I need help with this circuit, an RF oscillator

    Hello, Can somebody help, to understand the transistor, what does do 390pF and C(tune), and 4,3µH, they form tank circiuits? and also resistor 1K and capacitor .1, is possible somebody with little words to descirbe how it works please..... Thanks.
  9. M

    Hello, ferrite rod coupling inductor, I dont understand

    hi to everybody, can somebody tell me, ferrit rod coils, is a transformer? if yes how do you calculate? what is the formula how you select the coupling inductor L2 or L3......... because like i read the maing inductor must connect to capacitor(for frequency to find min and max i understand)...
  10. M

    Hi, I need help with a ferrite rod antenna please

    hello to everybody, can some help to make a ferrit rod antenna and to explain me thnx is for am radio, trf regenerative i have a ferrit rod 90mm diameter, and i have 0.5mm wire magnetic. this is the schematic , i make also the am receiver, but i dont know the ferrit rod(is problem i try to...
  11. M

    Hello, how can I replace a variable capacitor with a varicap

    hello, can somebody help me? i found this am receiver, but is using variable capacitor, how can i replace of do with varicap this circuits(i hava varicap bb112)
  12. M

    Hi, can somebody help to measure varicap diode

    Hello to everobody, i need help how works varicap can somebody explain how it works, how to measure i have bb205 VARICAP, i try to search on internet but i dont find something good, to learn thanks
  13. M

    Need to find an old variable capacitor

    hello i buy allmost all thing needed, for buil you own radio circuits 2013, but in electronics shop he told me , there are old, you can find it only in old radio he cant help, those components dont sell anymore, maybe somebody can help me how to find online those component VC1: two-gang...
  14. M

    Hi, can somebody explain this RLC circuit to me?

    Hello to everbody can you help me how come C6 to be 10p and c5 13.5 and and l1 to be 190n and L6 240n i start with 100Meghz, with one circuits 50/XL or 50/XC now become three different thanks i understand the first circuit, i understand the second circuit, but now they make three circuits how...
  15. M

    How to connect audio output to an ADC

    hello to everybody, can somebody help me, how to connect audio output to dac i have a rado tuner, i just need to connect audio output to adc after to connect to arduino thnx
  16. M

    Can somebody tell me the calaculations of this 2 transistor circuit?

    can somebody tell me this circuits calculations, how come 10mA please
  17. M

    3N187, where to find this type of MOSFET in LTSpice

    hello 3N187, where to find this type of mosfet in ltspice, , because i am reading one good book and i need this 3N187, any help is welcome
  18. M

    Please help me to buy an antenna coil

    please can somebody help, how to find in electronics shop online those components and to buy, is here juse one to make for all, i need juse one, wich i can use for all projetcs L1 antenna coil: 470uH with 1 turn wrapped = 2 L2 antenna coil: 470uH...
  19. M

    Hi one transistor radio help

    helo can somebody tell me how does work this circuits please, calculations and the rest
  20. M

    Hello -- audio transformer help

    hello can somebody help me, what can i use in place of audio transformer because i was in electronics shop the man he told they dont use anymore audio transformer in radio receiver what to use in place of audio transformer? thnx
  21. M

    How to calculate this 4 bit DAC

    < Mentor Note -- thread moved to HH from the technical forums, so no Homework Help Template is shown > please can somebody help me, how to calculate this 4 bit dac, i know this one if input 5/2, 5/4 5/8 5/16 voltage i dont understand nothing i search on the internet but i dont find...
  22. M

    Stray capacitance -- how to calculate formula...

    Hello, i am reading one book over the "tenichians radio receiver handbook", but there was a stray capacitance can somebody help me, how to calculate stray capacitance? of what arethe standard value of stray capacitance thanks. YES do you see the circuits the stray capacitance is 7pf and 320pf...
  23. M

    Hello everyone, can somebody with cascode amplifier

    Hello evervone can somebody help me, to calculate the cascade amplifier, if somebody can tell me the formula? of to explain me? i am reading the book "electronics devices circuit and theory" page 201-202 i dont know how come the value 2.50v, 1.25v, 1,87v see the photo down...
  24. M

    Please can somebody help me with TDA2050

    hello please can somebody help me i am a begginer i understeand everything just decoupling capacitor, i dont know te value how to select , of how to calculate C10, C7, C5 thanks
  25. M

    Assembler language help

    ; ; *** Listing 5.2 *** ; ; Program to illustrate one use of write mode 2 of the VGA and EGA by ; drawing lines in color patterns. ; ; Assembled with TASM 4.0, linked with TLINK 6.10 ; Checked by Jim Mischel 11/21/94 ; Stack segment para stack 'STACK' db 512 dup(0) Stack ends...
  26. M

    Please help transistor as switch help

    please can you help, explain me in easy way this circuit normal must be swith in position A q1 on q2 off q3 on switch in position B q1 off q2 on q3 off
  27. M

    Please help transistor amplifier

    can somebody teach mm how to find desired voltage gain of ce a transistor amplifier wich is formula, i know the formula is rc:rl/re but i want for example a voltage gain of 50 for example input desired data: desired voltage gain 2.0 wich i want to know f_min = 10 HZ z_in = 50 K...