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thank you Yas_Hashi for taking the trouble to go through the 34401 manual. Agreed with you on the loss is too high for my DUT. I never thought of checking the
spec...:idea:
Js, I think I got the idea now. sensitive lines voltage drop causes the DUT to fail to power up.
thanks again everyone
Hi,
I had been trying to measure the current drain of my project on the 1.5V step down dc/dc converter output line to a processor.
I am using 34401A mutimeter connecting in a series on the pcb trace out.
The problem is when I power up my DUT, the current drain is around 60-70+ mA but my DUT is...
This probably would have asked somewhere, may I ask when we pick a transistor, or when we want to study the reasoning of a transistor in a circuit,
in the transistor spec, what parameters, digit that you will first look for ? lets say the one in the attached. I know I need to check the bias...
Thanks you Audioguru, Deepikaaa and keith1200rs,
I now had some sense, and follow the lead to read on about the emitter follower.
This time I founded the original circuit has a voltage drop down at the source to lower the voltage for the mic and transistor bias. My finding also includes that it...
Attached is the schematic that I drafted out. Transistor is the BC847ALT1G.
The ac signal is to represents the microphone for small signal input.
so for the capacitors which is in pF values were for high frequencies bypass and
the remaining caps for uF were for audio amplification?
can I just...
Hi,
I come across a schematic on the microphone line, with a bjt which I believe is for audio signal amplification. I believe it is a common emitter type with Re=56 ohm. The thing is I don't understand why there is a capacitor with 39pF in between base and emitter, and another one 1000pF cap...
hello Paolo,
let us know how are you planning to match the loop antenna. There is a certain size of the loop
antenna. Last time I tried making a loop antenna with a copper tape, but I wasn't able to use it
because the antenna was matching at 2.4GHz with a relative big area size and had problem...
thank you. If you were me, would you still be re-matching the matching circuit after you know the degradation
of the cable influences surrounding the antenna?
Hello, I am having dilemma in measuring the bluetooth antenna performance. The problem I have is that there are unavoidable cables and flex nearby the monopole bluetooth antenna, typically the flex is < 1.5mm distance to the antenna while the cable is dangling around the antenna.
It has been a...
Thanks cnm. New findings from my test, I tried to measure conducted power after the matching, it has been reduced with the resistance in place. Really not a wise move.
I also realized one thing, this time without resistor, the higher i place for series inductor matching, the higher the loss...
Thanks Zorro,
Can you elaborate more on how the standard matching techniques? quarter-wavelength line ? do you mean by tuning the antenna length to
achieve quarter wavelength?
The BT antenna I have is ready made, the only thing left to do is just by using lump matching components.
thanks
I tried to tune a bluetooth antenna and found that with series inductor, it manage to shift to the horizontal line of the smith chart. It just need another 130ohm shunt resistance to horizontally move to the center of 50 ohm impedance.
Usually the matching involves inductors and capacitors...
hi,
just wondering how true this scenario is.
testing the range distance for an 800/900MHz band. For 800MHz can go until 5km distance average while at 900MHz band, the distance is only 3km. s11 and efficiencies are relatively good for both bands. Power levels are the same for both bands.
The...
vfone,
can you explain abit on your tip? really interested to know deep on this as I found out the parallel resonances are
due to the external flex which is very near to the antenna. should I look into shunt or series kind of capacitor matching?
I tried before a 22pF series and 10pF series, but...
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