NPN PNP coupling capacitor

[michael1978]

Hi, can somebody explain me how this circuits works? please, i dont understand input capacitor and C2 and C3. Thanks

 

[michael1978]

Hi, can somebody explain me how this circuits works? please, i dont understand input capacitor and C2 and C3. ThanksView attachment 40862

Hi i know input is input, and pnp emitter is to ground, but this C2 make it complicate for me.
so i ask with little words how does work?

 

[duke37]

What is the pupose of the circuit?
It looks to me to be a RF amplifier with Q! setting the current through Q2. The capacitors are to bypass RF current so to smooth the supply.
What are the component values?

 

[michael1978]

What is the pupose of the circuit?
It looks to me to be a RF amplifier with Q! setting the current through Q2. The capacitors are to bypass RF current so to smooth the supply.
What are the component values?

Hello, Duke, sorry for late answer, this is an form of bisasing on RF DESIGN

 

[AnalogKid]

Q1, R1, R2, and R5 form a constant current source to bias Q4 into its linear operating region without lowering the circuit's input impedance. C2 and C3 are bypass/decoupling capacitors to prevent the input RF signal from modulating the bias current and possibly forming an oscillator.

ak

 

[michael1978]

Q1, R1, R2, and R5 form a constant current source to bias Q4 into its linear operating region without lowering the circuit's input impedance. C2 and C3 are bypass/decoupling capacitors to prevent the input RF signal from modulating the bias current and possibly forming an oscillator.

ak

Thanks a lot man , now i understand.