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RF Input Continuity
Posted: Thu Aug 03, 2017 5:39 pm
by Sietedj
Hi, I have an FM amplifier that I'm doing.
I have verified that in the RF input there is continuity between the positive and the mass. I have no experience with these amplifiers and I do not know if it is normal or not, at the output there is no continuity. Can anyone tell me if it's normal or not?
Thanks and regards!!!
Re: RF Input Continuity
Posted: Fri Aug 04, 2017 3:12 pm
by Shedbuilt
Sietedj wrote: ↑Thu Aug 03, 2017 5:39 pm
Hi, I have an FM amplifier that I'm doing.
I have verified that in the RF input there is continuity between the positive and the mass.
Do you mean that the centre pin of the input, is connected (DC wise at least) to power ?
If so, you may find that the power is fed through a choke. It may be that it was designed to power the driver via the co-ax. Or it may be one of a few other possibilities (including a fault). If you're able to post a photo of the input side, it may help to figure out whether it is intentional or not.
Re: RF Input Continuity
Posted: Fri Aug 04, 2017 4:28 pm
by Sietedj
Shedbuilt wrote: ↑Fri Aug 04, 2017 3:12 pm
Sietedj wrote: ↑Thu Aug 03, 2017 5:39 pm
Hi, I have an FM amplifier that I'm doing.
I have verified that in the RF input there is continuity between the positive and the mass.
Do you mean that the centre pin of the input, is connected (DC wise at least) to power ?
If so, you may find that the power is fed through a choke. It may be that it was designed to power the driver via the co-ax. Or it may be one of a few other possibilities (including a fault). If you're able to post a photo of the input side, it may help to figure out whether it is intentional or not.
Hello, thanks for the answer. I already answered the manufacturer: Yes, it is normal. The first part of the input matching network is the spiral inductor which goes to ground. It is a short circuit at DC but not to RF.
Thanks for the interest!!!
Re: RF Input Continuity
Posted: Fri Aug 04, 2017 8:03 pm
by Shedbuilt
I think I get you now. When you said positive - in the first post, you meant the centre pin of the input. I thought you meant that the centre pin was connected to power supply positive. Glad you got it figured.
Re: RF Input Continuity
Posted: Sat Aug 05, 2017 6:26 am
by Sietedj
Shedbuilt wrote: ↑Fri Aug 04, 2017 8:03 pm
I think I get you now. When you said positive - in the first post, you meant the centre pin of the input. I thought you meant that the centre pin was connected to power supply positive. Glad you got it figured.
Maybe I explain it badly, since I do not speak English I have to translate with Google and sometimes it's complicated.
Re: RF Input Continuity
Posted: Sun Aug 06, 2017 10:55 am
by Maximus
Crikey! You're doing well using the translator
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