What is the purpose of connecting an inductor L to ground ?

[magneto_cool]

Detector Circuit Design

Hi
I have designed a simple detector circuit as shown in the diagram attached, baiscally i would know what is the purpose of connecting an inductor L to ground prior to diode because initially i do away with the inductor and connect the antenna directly to the diode however the detector does not work with out the added inductor to ground. Thus i hope any one can provide me with some enlightnement.

Many Thanks

 

[Borber]

Re: Detector Circuit Design

Rectification effect of diode is some DC current throught it. To enable DC current you need circuit where DC current can flow. Inductor at the front end of detector is there for that purpous. Even the video output must be terminated with propriate load resistor. The value of load resistor and capacitor determine the type of rectification you want. Result can be peak detection, envelope detection or average. In circuit with inductor, diode and load resistor a DC current can flow and rectification effect of a diode can be effectual.

 

[flatulent]

Re: Detector Circuit Design

The inductor should have a reactance at your operating frequency that is 5 times or more the impedance of the antenna. That way it does not "short out" the signal from the antenna.

 

[springf2000]

Re: Detector Circuit Design

that is a matched component of your diode,y can use the APPCAD to design your detector