Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Thanks for reply , I maybe didn't described what I need very clear
my question is :
Can I use that core which I have obtained from the SMPS as a RF transformer (to be used before the detector stage) ?
I am trying to design RF transformer specified for the Medium Wave
I got a core from a SMPS used as a filter at the dc output , its cylindrical in shape ,
2 cm length , 1/2 cm diameter
Can it be used for this task ?
or ferrite cores that used in RF applications have a special properties ?
OK guys all of that are fine , I am just confused about one thing
how to make the variable resistor at the base to get a center point
as I mentioned in the first post , I achieved to do that only when connected a resistor in series with the collector
and that was a bad idea as mentioned bellow...
I have modified the output RF transformer by increasing the impedance on the primary coil (transistor's side) to 160 uH (I wonder if that enough in case Medium Wave)
the gain have increased noticeably , the base is still need to be connected to the battery's positive terminal (no center point...
Thanks guys for the suggestions
I have to mention that I design that circuit to work on Medium Wave band range 530 - 1600 KHz
also I've forgot to describe my RF transformer at the output
its a Toko coil , I've rewound it as the following :
primary coil (transistor side) : impedance is about 23...
Trying to adjust the bias of the above circuit , I noticed that the 37 k pot need to be at its highest value ,
ie : the circuit need more positive voltage on the base
then the maximum gain I've got was when I connect the base to the ground (positive terminal by removing resistors & cap)
That...
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
