Good Sine wave amplifier

Thread Starter

micropad

Joined Dec 24, 2011
84
Dear All I have make a sine wave generator using ICL8083 IC for our school .

We need to show for our children about half wave and full wave rectification by applying this sine wave . Therefore we need to amplifier the output of the above IC, Please advice best method to amplify without any distortion

We are planing to connect 6v filament bulb as a load end of the rectification .

However output voltage can't be exceed more than 9v since we need to connect oscilloscope to the output
The oscilloscope that out school have UTD2052CL

Thanks in advanced
 
Last edited:

LesJones

Joined Jan 8, 2017
2,839
If you are just demonstrating rectification why do you have to generate it using a ICL8083 and then amplify it. Why not just use an isolating transformer with a low voltage secondary as a source of a sine wave ?

Les.
 

Thread Starter

micropad

Joined Dec 24, 2011
84
If you are just demonstrating rectification why do you have to generate it using a ICL8083 and then amplify it. Why not just use an isolating transformer with a low voltage secondary as a source of a sine wave ?

Les.
We need squire and sawtooth waves too and we need change the frequency also for other purpose
 

Thread Starter

micropad

Joined Dec 24, 2011
84
How much current do you need to light the 6V bulb?
Why not use a LED which take a lot less current?
Around 500mA

Our project have a bulb that connected parallel to the diode , The we can show to students when bulb is connected the current go via the bulb
 

neonstrobe

Joined May 15, 2009
131
A 6V lamp on AC needs +/-9V so the power supply for a single ended amp will need to be 18V or more.
Depending on how much current your 9V can supply you could make a simple inverter too to generate -9V. There are a number of small Dc-DC converters around which may be of use. Preferably, I'd get a couple of converters to give +/-12V and run a power amp IC from those.
 

neonstrobe

Joined May 15, 2009
131
Your oscilloscope does not seem to be limited to 9V with a 20V/div scale.
If it is your power supply then what about using DC-DC converter(s) to provide -9V or +/-12V?
 

MrAl

Joined Jun 17, 2014
7,891
Dear All I have make a sine wave generator using ICL8083 IC for our school .

We need to show for our children about half wave and full wave rectification by applying this sine wave . Therefore we need to amplifier the output of the above IC, Please advice best method to amplify without any distortion

We are planing to connect 6v filament bulb as a load end of the rectification .

However output voltage can't be exceed more than 9v since we need to connect oscilloscope to the output
The oscilloscope that out school have UTD2052CL

Thanks in advanced

Hello there,

If you intend to get 6v ac out then the peak will be about 8.5 volts. To get that kind of sine wave from a 12v DC power source means you have to use a bridged amplifier because you need plus and minus 8.5 volts peak output. This means a single op amp will not work you will need at least two op amps set up in a bridge configuration. It will be harder if you use transistors but you can in fact do that too, also in a bridge configuration which means you have to construct two amplifiers.

For a bridged configuration, one amp is made to invert the signal, the other to not invert the signal. The output is taken from the two amplifier outputs not from one output to ground.
 

neonstrobe

Joined May 15, 2009
131
I recommend, again, using a DC-DC converter so that you can use a single amplifier.
From what the TS said, he wants to be able to rectify the output with various load configurations. That is going to be simpler if the output is from one amplifier and ground, is it not?
 

MrAl

Joined Jun 17, 2014
7,891
I recommend, again, using a DC-DC converter so that you can use a single amplifier.
From what the TS said, he wants to be able to rectify the output with various load configurations. That is going to be simpler if the output is from one amplifier and ground, is it not?
Well there are differences. If you use a DC to DC converter to first step up the voltage then the output will have to be capacitively coupled. With a bridged amplifier configuration that wont be needed unless maybe there is an imbalance in the output (DC offset).
 

LesJones

Joined Jan 8, 2017
2,839
The problem with a single supply amplifier for the TS's purpose of demonstrating rectification is it will have an output capacitor to block the DC component of the amplifier. This would cause confusing results demonstrating half wave rectification as the capacitor would charge up. This could be overcome with a transformer on the output but getting one that worked over the frequency range required by the TS could be a problem. What is the exact specification of the 12 volts limit ? does this exclude 12 volts AC as the peak voltage is 17 volts ? I was thinking that a ready made amplifier with only the output terminals accessible to the students would solve the problem.

Les.
 

neonstrobe

Joined May 15, 2009
131
Well there are differences. If you use a DC to DC converter to first step up the voltage then the output will have to be capacitively coupled. With a bridged amplifier configuration that wont be needed unless maybe there is an imbalance in the output (DC offset).
I was thinking of generating a -12V supply from the +12V and using a direct coupled output. As others have said, it was not my consideration to use a single ended design with an output capacitor.
You only need an isolating converter for that. Probably any of the old fashioned saturating core designs are simplest and easiest (cheapest) to build, if sometimes a bit squeaky and needing an LC filter in the output. I find putting it in a suitable box and cementing everything down cuts the noise, and have had two 12V to +/-35V supplies running amps for more years than I care to think of!
 

MrAl

Joined Jun 17, 2014
7,891
I was thinking of generating a -12V supply from the +12V and using a direct coupled output. As others have said, it was not my consideration to use a single ended design with an output capacitor.
You only need an isolating converter for that. Probably any of the old fashioned saturating core designs are simplest and easiest (cheapest) to build, if sometimes a bit squeaky and needing an LC filter in the output. I find putting it in a suitable box and cementing everything down cuts the noise, and have had two 12V to +/-35V supplies running amps for more years than I care to think of!
Hi,

I guess you can do that too. Dont need an isolating inverter though it just has to generate -12v relative to the existing ground. There are DC converters that can do that with just an inductor for the power conversion part. Not a bad idea really.
 
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