Author Topic: Siglent SDG1000x and .01uf capacitor  (Read 599 times)

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Offline Topwater

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Siglent SDG1000x and .01uf capacitor
« on: January 21, 2022, 06:01:12 pm »
I'm getting in to cb radio repair and recently purchased a SDG1000x generator.  My radio repair manuals say to put a .01uf capacitor in series with a signal generator test lead.  It is an old manual.  Is a .01 cap necessary with my Siglent SDG1000x, or does the sdg1000x  internal overvoltage protection do the same thing?  Is the purpose of a .01uf cap to block DC from the radio reaching the signal generator?

Offline Vovk_Z

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Re: Siglent SDG1000x and .01uf capacitor
« Reply #1 on: January 21, 2022, 10:42:57 pm »
It is rather to prevent DC from outer circuit to radio. There mustn't be direct DC coupling. AC coupling is allowed only.
So, you still have to use 0.01 uF cap.
« Last Edit: January 21, 2022, 10:44:47 pm by Vovk_Z »

Offline TimFox

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Re: Siglent SDG1000x and .01uf capacitor
« Reply #2 on: January 21, 2022, 10:56:35 pm »
Normally, the output from the signal generator should look like 50 ohms to ground at DC, which may not be appropriate for the circuit that you are driving.  Hence the need for a "DC blocking" capacitor.  10 nF in a 50 ohm circuit gives a corner frequency of < 1 MHz, which will pass everything you need at RF.

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