Wow that is so great, until now used to draw and calculate the matching networks by hand! It worked perfectly, I really felt like an engineer from the future doing that!
@@polprog702 I used to use QUCS, but it gives weird error reporting. I change one capacitor value, it then shows an error. If I change it back to the original value, it still shows an error!
Hi. I'm just curious: how do you determine the 1nF capacitor at the input? Is it by using the C=Q/V equation or the Xc equation or both? I'm sorry if this is a weird question to ask😅
Agree - mouth noises spoilt an otherwise super video . He could use audacity with a plug in to remove these , or perhaps not have the mic pickup inside the mouth .
I would think it needs a capacitor at the output, between the 50 ohm resistor and collector. With 50 ohms and a DC voltage present, it will alter the DC load line!
![Gain block RF Amplifiers - Theory and Design [1/2]](http://i.ytimg.com/vi/8myFI-tmowo/mqdefault.jpg)
Wow that is so great, until now used to draw and calculate the matching networks by hand! It worked perfectly, I really felt like an engineer from the future doing that!
Great video and great method to match the impedance!
Where can i download the Smith 4.1 tool?
I have the rereflection coefficient and would like to import it into the Smith 4.1 tool. Is this possible and if so I would appreciate a short video.
why did we add 50 ohm resistor to the output?
Nice info.. thanks!
Hi if my center frequency is 900Meg what would my start and stop frequency be?
I think it can be anything, you can try 450 to 1800MHz
any refrence for using this method for impedance matching?
You can use it to sweep a circuit across some band but I think QUCS-S is better for that as it does Smith charts and S-parameter plots
@@polprog702 I used to use QUCS, but it gives weird error reporting. I change one capacitor value, it then shows an error. If I change it back to the original value, it still shows an error!
Hi. I'm just curious: how do you determine the 1nF capacitor at the input? Is it by using the C=Q/V equation or the Xc equation or both? I'm sorry if this is a weird question to ask😅
I think it was from the top of my head. At this frequency 1nF is a very low impedance. edit: from the Xc equation.
great tutorial, i tried same using my bjt transistor deign, but am getting negative as my real part
Hm, that is weird, but maybe LTspice took the current draw in the other direction. Just drop the minus from the real part
This video shows how to install LTSpice: th-cam.com/video/g5t4C2UdKJI/w-d-xo.html
But how to install Smith 4.1 - it seems not free software.
Great video. Drink some water u seems thirsty!!
Agree - mouth noises spoilt an otherwise super video . He could use audacity with a plug in to remove these , or perhaps not have the mic pickup inside the mouth .
The circuit should have a capacitor coupling the output
that's true, though in practice I put a large one like 100n that has neglible impedance and dont always draw it
@@polprog702 It will have a neglible impedance, but will change the DC operating parameters of the transistor, which will affect the matching?
I would think it needs a capacitor at the output, between the 50 ohm resistor and collector. With 50 ohms and a DC voltage present, it will alter the DC load line!
@@JonathanS-q7n You're right, I did not notice that
LTSPICE is not for RF use. you need to use HAM radio amateurs ' tool, way much better. probably 100 magnitude better.
It is for RF use if you understand its limits