Why is a battery needed in a radio receiver
By Odud - usenet poster
if we take a simple radio receiver, at which stage of the reception
process is the battery needed? the antenna does not need a battery,
that i know, the amplifier does need it - that is also obvious, but
what about all the things that happen in the middle? ( tuner
(capacitators), detector (resonator) etc. )Which is the first element
that will prevent reception if the receiver is not equipped with an
external power source?
Best Solution
posted on Aug 02, 2007
Grant - usenet poster
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Hi Jeff,
thanks for the post. It is a theoretical question - I am discussing
with a friend (who is a an electrical engineer that already forgotten
the basics :) ) why we need a battery in his walkman. He says that it
is needed only for the amplifier, I say we also need external power
for the resonator, otherwise it won't oscillate.
thanks for the post. It is a theoretical question - I am discussing
with a friend (who is a an electrical engineer that already forgotten
the basics :) ) why we need a battery in his walkman. He says that it
is needed only for the amplifier, I say we also need external power
for the resonator, otherwise it won't oscillate.
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Solution #2
posted on Aug 02, 2007
Bray - usenet poster
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On 12 Aug 2002 01:14:02 GMT, (Dbowey) wrote:
Y'er right, I goofed. (I hate it when that happens). I forgot about
the first local oscillator. It would be the first component in
receiver chain that would require power.
--
Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
(831)421-6491 pgr (831)336-2558 home
# WB6SSY
-cruz.ca.us
Y'er right, I goofed. (I hate it when that happens). I forgot about
the first local oscillator. It would be the first component in
receiver chain that would require power.
--
Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
(831)421-6491 pgr (831)336-2558 home
# WB6SSY
-cruz.ca.us
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Solution #3
posted on Aug 02, 2007
kioner - usenet poster
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Some require a battery for memory of preset stations.
Other than that, each stage of amplification, input to output,
signal processing, whatever requires some power supply.
Jeff
Other than that, each stage of amplification, input to output,
signal processing, whatever requires some power supply.
Jeff
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Solution #4
posted on Aug 02, 2007
Brad - usenet poster
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<< If your unspecified receiver has a passive front end mixer stage
(double balanced mixer), there is no power required at the mixer
Say, Jeff, you seem to ignore the local oscillator that will be driving the
double balanced mixer. You might want to take another look at your mixer
theory.
Don
(double balanced mixer), there is no power required at the mixer
Say, Jeff, you seem to ignore the local oscillator that will be driving the
double balanced mixer. You might want to take another look at your mixer
theory.
Don
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Solution #5
posted on Aug 02, 2007
Mini Me - usenet poster
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On 11 Aug 2002 04:57:21 -0700, (sara) wrote:
Is this a theoretical question?
There are such things as "free power" receivers, that do not have any
external power source. The problem is that without amplification, the
power output at the speaker/ear-phone is no more than the detected
power at the antenna. In general, they pickup power from ALL radio
stations, rectify it, and use it to run the amplifier stages of the
receiver.
If your unspecified receiver has a passive front end mixer stage
(double balanced mixer), there is no power required at the mixer. In
1-20MHz receivers, atmospheric noise obliterates the sensitivity
benifits derived from an RF amplifier. Therefore, many HF receivers
have no active components in the RF section and consists only of
filters. So, a simple HF receiver might consist of a passive RF
section, a passive mixer, and a passive first IF filter. However,
after the first IF filter, you gotta have some gain. That's where the
first stage the requires power is located.
I suspect this is not what you're interested in determining. Perhaps
it would help if you disclosed what you are trying to accomplish and
what you have to work with?
--
Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
(831)421-6491 pgr (831)336-2558 home
# WB6SSY
-cruz.ca.us
Is this a theoretical question?
There are such things as "free power" receivers, that do not have any
external power source. The problem is that without amplification, the
power output at the speaker/ear-phone is no more than the detected
power at the antenna. In general, they pickup power from ALL radio
stations, rectify it, and use it to run the amplifier stages of the
receiver.
If your unspecified receiver has a passive front end mixer stage
(double balanced mixer), there is no power required at the mixer. In
1-20MHz receivers, atmospheric noise obliterates the sensitivity
benifits derived from an RF amplifier. Therefore, many HF receivers
have no active components in the RF section and consists only of
filters. So, a simple HF receiver might consist of a passive RF
section, a passive mixer, and a passive first IF filter. However,
after the first IF filter, you gotta have some gain. That's where the
first stage the requires power is located.
I suspect this is not what you're interested in determining. Perhaps
it would help if you disclosed what you are trying to accomplish and
what you have to work with?
--
Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
(831)421-6491 pgr (831)336-2558 home
# WB6SSY
-cruz.ca.us
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Solution #6
posted on Aug 02, 2007
kioner - usenet poster
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There isn't one.
Do a search on "crystal radio".
However, if a sensitive radio, or one that does more than output into
sensitive headphones is needed, then you need to amplify the
signal.
This needs some sort of power.
--
# | mailto: | Ian Stirling.
++
If God hadn't intended us to eat animals,
He wouldn't have made them out of MEAT! - John Cleese
Do a search on "crystal radio".
However, if a sensitive radio, or one that does more than output into
sensitive headphones is needed, then you need to amplify the
signal.
This needs some sort of power.
--
# | mailto: | Ian Stirling.
++
If God hadn't intended us to eat animals,
He wouldn't have made them out of MEAT! - John Cleese
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