Amplifier
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Posts: 46,084
I need to learn about audio amplification. I made a simple circuit
that produces sine wave and put it to a very small speaker (the Radio
shack project variety). Now I need it to be amplified and I am
thinking of using an amplified computer speaker (monitor speakers. Is
it a matter of taking the two wires going to the speaker and putting
them into the input line on the monitor speaker?
Where can I learn about matching audio impedence, minimizing noise,
amplification etc. Please recommend some electronics books or website
that I can check out.
many thanks
al
that produces sine wave and put it to a very small speaker (the Radio
shack project variety). Now I need it to be amplified and I am
thinking of using an amplified computer speaker (monitor speakers. Is
it a matter of taking the two wires going to the speaker and putting
them into the input line on the monitor speaker?
Where can I learn about matching audio impedence, minimizing noise,
amplification etc. Please recommend some electronics books or website
that I can check out.
many thanks
al
Comments
rather than wait for a day to see if the clock is slow or fast I want to use
a "tic" to start a timer and the next "tic" or even the next 15 or 60 to
stop the timer. I then can rapidly set the speed regulator for the old
mechanical clock.
I need help with the amplifier - I would like to hold a microphone near the
clock movement and have the electronics make a 0 to 5 volt transition.
I have tried an audio amp with (op-amp) with gain of 100 - not much luck
any one have any good ideas?
thanks
richard
All the parts can be picked up at radio shack. I have built this stereo
amplifier and it works incredible. It can be built in an evening or two.
Of course if you want a mono output then you only have to build one of the
two channels that are shown on the schematic found at that website. The
design uses LM386 audio op-amps and the design needs no tweaking. It works
really well.
Jim
Original Message
From: <alnajjar@s...>
To: <basicstamps@egroups.com>
Sent: Thursday, January 25, 2001 5:23 PM
Subject: [noparse][[/noparse]basicstamps] Amplifier
> I need to learn about audio amplification. I made a simple circuit
> that produces sine wave and put it to a very small speaker (the Radio
> shack project variety). Now I need it to be amplified and I am
> thinking of using an amplified computer speaker (monitor speakers. Is
> it a matter of taking the two wires going to the speaker and putting
> them into the input line on the monitor speaker?
>
> Where can I learn about matching audio impedence, minimizing noise,
> amplification etc. Please recommend some electronics books or website
> that I can check out.
>
> many thanks
>
>
> al
>
>
>
First a few questions:
1) What is the voltage swing from the audio amp that is driven by the
microphone when the "tick tock" sound is present? A gain of 100 may not be
enough to drive the audio amp from zero to +5 volts.
2) If the audio output swing is less than 5 volts, I suggest you consider
driving a comparator from the audio amp. An operational amplifier can be
connected as a comparator and hysteresis should be used to reduce the amount
of noise as the input signal goes through the switching point. The power
supply for the comparator should be 5 volts or the output of the comparator
should be limited to +5 volts. This can be done with a two resistors and a
pair of signal diodes (1N914 or 1N4148) connected in the following manner:
+5
l
D1
l
comparator output >
R1
@
R2
>input to Basic Stamp
l
D2
l
ground
R1 is 4.7K ohms / R2 is 1.0K ohms
D1 cathode connected to +5 volts, anode connected to junction of R1 and R2.
D2 cathode connected to junction of R1 and R2, anode connected to ground.
Hope this helps. Burt
1) Do the computer monitor speakers have an intenal amplifier? If yes, how
much power are they capable of delivering? Suggest you open the case and
examine the inside. If no, then a simple amplifer is needed. Radio Shack
had or has audio amplifers that can be powered by 6 or 9 volts. From your
email, it sounds like you are trying to amplify a sine wave. Is this
correct? What power level do you need?
2) Books about audio can be found in many places including the ARRL Radio
Amateur Handbook, TAB and SAMS publications have several books on audio,
there are a couple of magazines such as the 'Audio Amateur" that can be found
at your Borders or Barnes and Noble book stores. Have you tried your local
library and the TAB and SAMS websites?
3) I am looking forward to your response to my email to you from earlier
this week about getting started with the Basic Stamp.
Hope this helps, Burt/burtsz@a...
intranet with a virus - I lost many files - poor backup - lost all my stamp
files (I can retype them in again because I had paper back up - and my
internet server dropped me (actually our whole town)
please respond to
rfriedrich@a...
Original Message
From: <burtsz@a...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, January 26, 2001 6:31 AM
Subject: Re: [noparse][[/noparse]basicstamps] Amplifier
> Hi Al,
>
> 1) Do the computer monitor speakers have an intenal amplifier? If yes,
how
> much power are they capable of delivering? Suggest you open the case and
> examine the inside. If no, then a simple amplifer is needed. Radio Shack
> had or has audio amplifers that can be powered by 6 or 9 volts. From your
> email, it sounds like you are trying to amplify a sine wave. Is this
> correct? What power level do you need?
>
> 2) Books about audio can be found in many places including the ARRL Radio
> Amateur Handbook, TAB and SAMS publications have several books on audio,
> there are a couple of magazines such as the 'Audio Amateur" that can be
found
> at your Borders or Barnes and Noble book stores. Have you tried your
local
> library and the TAB and SAMS websites?
>
> 3) I am looking forward to your response to my email to you from earlier
> this week about getting started with the Basic Stamp.
>
> Hope this helps, Burt/burtsz@a...
>
>
>
I tried boosting the gain to 1000 and all it did was oscillate - about then
all my computers went down with a virus, I screwed them up some more and my
back ups were almost a year old.
duh, I guess I wont rely so heavily on anti-virus software.
richard
Original Message
From: <burtsz@a...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, January 26, 2001 6:18 AM
Subject: Re: [noparse][[/noparse]basicstamps] Amplifier
> Hi Richard,
>
> First a few questions:
> 1) What is the voltage swing from the audio amp that is driven by the
> microphone when the "tick tock" sound is present? A gain of 100 may not
be
> enough to drive the audio amp from zero to +5 volts.
> 2) If the audio output swing is less than 5 volts, I suggest you consider
> driving a comparator from the audio amp. An operational amplifier can be
> connected as a comparator and hysteresis should be used to reduce the
amount
> of noise as the input signal goes through the switching point. The power
> supply for the comparator should be 5 volts or the output of the
comparator
> should be limited to +5 volts. This can be done with a two resistors and
a
> pair of signal diodes (1N914 or 1N4148) connected in the following manner:
> +5
> l
> D1
> l
> comparator output >
R1
@
R2
>input to Basic Stamp
> l
> D2
> l
> ground
>
> R1 is 4.7K ohms / R2 is 1.0K ohms
> D1 cathode connected to +5 volts, anode connected to junction of R1 and
R2.
> D2 cathode connected to junction of R1 and R2, anode connected to ground.
>
> Hope this helps. Burt
>
>
>
its periodic motion either optically or with a Hall effect sensor instead of
using audio, for simpler electronics. Using a Stamp, you could time N clock
ticks with elapsed time from a crystal-based counter. Let N be a power of 2
for easy division. For ultimate accuracy, embed an Oregon Scientific atomic
clock inside your old clock -- somewhat like using a modern computer chip to
calibrate Babbage's Calculating Engine at the British museum.
Dennis
Original Message
From: dakota [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=lody3EOJBjhBJ_Wrc_78j8E0SdFn0lsUa-3dnHWzgIhvxQChaHT7I-LMhVFI3IxESn3C1Ik4GWKJC7HZs0QFY4pF]rfriedrich@a...[/url
Sent: Thursday, January 25, 2001 3:34 PM
To: basicstamps@egroups.com; basicx@egroups.com
Subject: [noparse][[/noparse]basicstamps] Amplifier
I want to make a stamp project to set the fast/slow control on an old clock
rather than wait for a day to see if the clock is slow or fast I want to use
a "tic" to start a timer and the next "tic" or even the next 15 or 60 to
stop the timer. I then can rapidly set the speed regulator for the old
mechanical clock.
I need help with the amplifier - I would like to hold a microphone near the
clock movement and have the electronics make a 0 to 5 volt transition.
I have tried an audio amp with (op-amp) with gain of 100 - not much luck
any one have any good ideas?
thanks
richard