AT1 question

[Harlan Sherriff]

It must be my old age setting in but I can't get my head on right.

I have an AT1 attenuator I just finished assembling. My understanding of dB attenuation must be off.

If I use an input of 1 volt, shouldn't I expect 0.1 volt out if I have selected 20 dB attenuation?

Harlan
NC3C

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[Roger D Johnson]

Only if you have the attenuator terminated properly!

On 6/6/2014 2:57 PM, Harlan wrote:

> It must be my old age setting in but I can't get my head on right.
>
> I have an AT1 attenuator I just finished assembling. My understanding of dB attenuation must be off.
>
> If I use an input of 1 volt, shouldn't I expect 0.1 volt out if I have selected 20 dB attenuation?
>
> Harlan
> NC3C
>
> Sent from my Verizon Wireless 4G LTE DROID
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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[Harlan Sherriff]

Ok all...... The 50 ohm load must be it. I was using a Fluke 5520A calibrator and a Fluke 8508A Reference Multimeter to read the output WITHOUT a load....

Been a long day.
Thanks to all....
Harlan
NC3C

Sent from my Verizon Wireless 4G LTE DROID

Ralf Wilhelm <[hidden email]> wrote:

>Harlan,
>
>You should get 0.1 volts when you terminate your attentuator with 50 Ohms - are you probably using a high z voltmeter? The output of the attentuator can be seen as a 0.2 V voltage source with 50 ohms internal resistance - if you terminate it with a 50 ohms load, the 0.2 volts are divided between the internal resistance and the load, but if you use a high z termination instead, the voltage drop on across the high z is 0.2 volts...
>
>Greetings
>
>Ralf, DL6OAP
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