0
\$\begingroup\$

Recently I have been working on a basic RF receiver, but my efforts so far have proved fruitless. I designed the following circuit based of of previous research into the topic. According to what I read, I need the LC tank circuit connected to an antenna so the LC circuit resonates at the frequency based of the inductor and the capacitor. The signal is then fed through a germanium diode into a transistor which should amplify the signal. Am I correct? Do you think this circuit will amplify the incoming signal? (I don't have the proper equipment to measure the oscillations and, as far as I could tell, it isn't working) Sorry for the bad schematic. I'm not very good with drawing circuits on the computer. Thanks for any advice.

enter image description here

\$\endgroup\$
  • \$\begingroup\$ Sorry the image and text seem to be messed up for some reason. \$\endgroup\$ – Sock314 Aug 31 '14 at 20:34
  • 3
    \$\begingroup\$ Your output is connected directly to your power supply. You need a collector resistor to develop the output voltage across. Also you have sno ource of bias current for the base of your transistor. Are you familiar with biasing transistors so they operate in their linear region? I think you need to do more research. \$\endgroup\$ – Barry Aug 31 '14 at 22:10
  • \$\begingroup\$ Yeah I am familiar with biasing the base. So if I were to fix the errors you described would it, theoretically, work? Thanks for you input. \$\endgroup\$ – Sock314 Aug 31 '14 at 22:52
  • \$\begingroup\$ With a good antenna and with the transistor biased properly, it could work but you will probably only be able to receive strong AM broadcast stations. \$\endgroup\$ – Barry Sep 1 '14 at 2:26
1
\$\begingroup\$

Your schematic does resemble a basic radio receiver, but the whole thing is a lot more complicated than that. The LC circuit needs to be tunable, the choice of transistor is an important one (as well as correctly biasing it), that resistor should probably be on the collector side, you'd need something on the output to indicate what kind of signal is present, etc... And you do need equipment for measuring oscillations, unless you hope to come up with a working configuration of parts by accident. Or at least you'd need to thoroughly simulate the circuit before there's any point in building it.

If you really want to build your own radio receiver, you'll need to know a lot about filters and amplifier circuits... Or follow detailed plans that someone has made, with detailed component values and all; I'm sure you can find some with a bit of googling :-)

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.