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Home > Archive > Electrical Engineering > September 2007 > average volts to dc
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average volts to dc
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| Warren Thai 2007-09-15, 8:25 pm |
| I need a circuit to take in a PWM signal (Vin) and output the average
voltage (Vo = D*Vin). Any ideas?
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| Salmon Egg 2007-09-15, 8:25 pm |
| On 9/15/07 3:53 PM, in article
46ec6230$0$7087$afc38c87@news.optusnet.com.au, "Warren Thai"
<wthai1@optusnet.com.au> wrote:
> I need a circuit to take in a PWM signal (Vin) and output the average
> voltage (Vo = D*Vin). Any ideas?
>
>
Use a d'Arsonval meter. No electronics or power supply is necessary.
Bill
--
Fermez le Bush--less than 18 months to go.
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| ng2007@saXuna-aXho.com 2007-09-16, 1:25 pm |
| On Sun, 16 Sep 2007 08:53:00 +1000, "Warren Thai"
<wthai1@optusnet.com.au> wrote:
>I need a circuit to take in a PWM signal (Vin) and output the average
>voltage (Vo = D*Vin). Any ideas?
>
>
Use a low pass filter and put the PWM frequency
far over the filter's cut-off frequency.
(Remove the two Roentgen-ray characters to reply.)
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| dave y. 2007-09-17, 8:25 pm |
| On Sun, 16 Sep 2007 08:53:00 +1000, "Warren Thai"
<wthai1@optusnet.com.au> wrote:
>I need a circuit to take in a PWM signal (Vin) and output the average
>voltage (Vo = D*Vin). Any ideas?
>
The low pass filter (e.g. resistor-capacitor) is the obvious first
answer, but how about also requiring a fast response time?
Now I'm thinking maybe a switched integrator. Any other ideas?
dave y.
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| Palindrome 2007-09-18, 3:25 am |
| Warren Thai wrote:
> I need a circuit to take in a PWM signal (Vin) and output the average
> voltage (Vo = D*Vin). Any ideas?
>
>
As others have suggested, there are analogue methods of averaging, using
mechanical, electrical or thermal techniques.
However, as this is presumably a fixed amplitude signal, simple digital
techniques are also available using the timing of the edges of the signal.
I won't mention the device-type of choice, as (1) everyone knows what it
is and (2) some go spare just at the mention of the acronym.
It will have many advantages - including that of a much faster response
time than any analogue system - as it will produce a valid output almost
immediately after the first pulse has been registered. However, it will,
of course, produce a quantised output signal which may need analogue
techniques to reduce the transient component.. ;)
--
Sue
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