boost function generator output

Thread Starter

roadey_carl

Joined Jun 5, 2009
134
Hello everybody, hope your all well.

I've recently brought some more electronics equipment including a rigol DS1052E 50mhz oscilloscope and a vector 2002 2Mhz function generator.

I'd like to boost the output of the function generator current and voltage if passable.... I was messing around with some transistors and I could boost it around 200mA but only 1 side of any wave form because the other was at ground.

I measured the short circuit output at 10v and got just under 110mA. Id like to be able to add an external PSU to power the circuit, 1-60vdc at about 1A, maybe a bit more if passable, I need it to be able to output 5-500Khz?

Could anybody recommend a amplifier capable of doing this?

here is a link for the spec of the function generator :
http://www.gainexpress.com/product_info.php?products_id=836&osCsid=aqbegvc8elhaov38rhd60me6j2

Thanks for your brains!
 

mik3

Joined Feb 4, 2008
4,843
A function generator can output positive and negative voltages. You will need a dual supply plus an amplifier. The amplifier can be an op-amp preamplifier (for voltage amplification) and a push-pull transistor pair driven by the op-amp to boost current.
 

PaulEE

Joined Dec 23, 2011
423
A function generator can output positive and negative voltages. You will need a dual supply plus an amplifier. The amplifier can be an op-amp preamplifier (for voltage amplification) and a push-pull transistor pair driven by the op-amp to boost current.
To bring the above post "home", take a look at something like the LM3886 class AB audio amplifier chip. It is exactly what is described above and all in one package.

Just get yourself (or build yourself) a nice split supply, hook up the LM3886, and off you go.
 

mik3

Joined Feb 4, 2008
4,843
To bring the above post "home", take a look at something like the LM3886 class AB audio amplifier chip. It is exactly what is described above and all in one package.

Just get yourself (or build yourself) a nice split supply, hook up the LM3886, and off you go.
Are you sure it can operate satisfactorily at frequencies above 20kHz?
 

Thread Starter

roadey_carl

Joined Jun 5, 2009
134
Hi again,

I brought a TDA2050 audio amplifier but I'm not to sure how to set it up. Id like to connect my sine wave output from a function generator to the input.

Theres a couple of things I'm not so sure of and was hoping someone could help?

1: the dual PSU. is the ground where C7 and the speaker is connected to?
the positive to the IC is pin 5 + and negative pin 3 - ?
2: would I connect my input from the function generator to the inverting and non-inverting input? and this will pick up both the positive and negative cycle?

I'm using the circuit on page 4 of the attached PDF.
http://www.datasheetcatalog.org/datasheet/stmicroelectronics/1461.pdf

Thanks again.
 

PaulEE

Joined Dec 23, 2011
423
Are you sure it can operate satisfactorily at frequencies above 20kHz?
Good call. I didn't see the 20 kHz to 200 kHz spec.

It can, but the peak-to-peak output is limited to around 10 Vpp.

High frequency and high amplitude start to add to price with op-amps - in my experience, anyway.

As far as the chip you ended up getting...

I think it's going to get distorted approaching 100 kHz, or, at least, the amplitude will start to go down. This will be most noticeable at high frequencies or high peak-to-peak switching, as in square waves.

Answer to #1: Yes, yes, and yes. All the leads that terminate with a horizontal line, like those on the speaker, that cap, etc..are ground.

Answer to #2: You'd hook up the input of the generator between "Vin" and ground.
 
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