Could somebody please suggest which function generator to buy.

I am at the intermediate stage of electronics and would like to move into the area of basic fault finding. Later I would like to explore the area area of RF electronics.

I'vce had a look at whats on ebay and would like some advice from a more experienced person than myself. My budget is £200 at a push.

Many Thanks -JDR04

 

You should define the range of frequency that you want, see as below.

Radio frequency.
Radio spectrum.
RF Basics, RF for Non-RF Engineers.

 

In terms of essential tools for the electronics hobbyists I would list the following:

Wire stripper
Needle nose pliers
Set of hand tools
Soldering station
DVM
Oscilloscope
Variable power supply
Function generator

Since you mention that you are at the intermediate stage I assume that the function generator is the last item on your list as well.

Someone on a budget can make do with a DIY circuit that would cost from £1 to £10.
If you want a commercial unit, a basic FG that outputs sine, square and triangular waves, from 0 to 3MHz should be no more than £100.

I have not explored RF generators. As Scott has said, you need to define your RF range. I would have no need for an FG exceeding 30MHz. (even though I am a licensed ham)

 

Thanks guys, I think ScotWang raised a very good point about RF. As that is going to be in the distant furture for me, I'll leave RF out of the equation.

The links below are the function gernerators I have been considering. Any input/guidance from you will be appreciated.

http://www.ebay.co.uk/itm/Function-...uipment_ET&hash=item51b1c4d721#ht_2155wt_1170

http://www.ebay.co.uk/itm/GW-Instek...ultDomain_3&hash=item565b2a36a9#ht_1290wt_932

http://www.ebay.co.uk/itm/ATTEN-ATF...cilloscopes&hash=item27d713e78b#ht_4257wt_915

Thanks for your input-JDR04

 

Your first two links show identical FG.
Personally, I definitely would NOT get the one in the third link.

 

I just did a little research on this subject...

I ended up buying a old 90's version Tektronix for $112 USD (£70) after shipping. Some of the reviews I saw of the newer lower quality generators showed a lot of jitter at low frequencies. The tek I ended up with was stable over the entire range of frequencies (3MHz). It's probably a bit out of cal... there's a trim pot somewhere that probably needs tweaked. I am very pleased. It also goes well with my scope of the same era.

 

Thething that worried me about the first function generator was when I read the "specs" they looked rather short on description. It also mentioned a voltage display as well. I'm not sure if this is to display amplitude or can be used as a multimeter. This would be a waste for me as I already have a perfectly good Fluke 179.

So, I'm really no further forward except been warned off the third one by MrChips.

It look to me that one should rather pay more for a better quality unit as opposed to a fancy one with all the bells and whistles.Am I right??

Any other suggestions out there???

 

Have you decide how high of the frequency you want to play with, and many kinds of the waveform you need to use?

 

I'd suggest getting a older name brand unit... Tek, Agilent, or HP. I think Tek was called Telequipment in the UK. Chances are good that the unit will still work.

Here's the same model that I bought the other day - It's a great general purpose function generator.
http://www.ebay.com/itm/Tektronix-C...704?pt=LH_DefaultDomain_0&hash=item3f2a775aa0

There are some on there for much cheaper, but I couldn't verify overseas shipping.

 

BK and GW are not the best brands but you wouldn't have to break the bank.

 

Thanks guys, I found these two and am wondering what your opinions would be;

http://uk.farnell.com/digimess/fg303/generator-function-dds-3mhz/dp/2146612

http://uk.farnell.com/digimess/fg308/generator-function-dds-8mhz/dp/2146613

I'm not familiar with the brand mame of DIGIMESS. Perhaps someone out there can shed more light. Thanks again - JDR04

 

Do you need the digital display?

If I were on a budget I would consider the 8015G:

http://uk.farnell.com/gw-instek/gfg-8015g/function-generator-analogue-2mhz/dp/4911684

 

Thanks MrChips, your suggestion is appreciated. My budget is £200. If I can't find something with a readout then I'll go for the one you suggested.

I see some of them have DDS as a feature.What is the significance of this?

Thanks again -JDR04

 

DDS means Direct Digital Synthesis. This means that it uses digital microcontroller technology to select the frequency using numerical input rather than by turning a variable resistor in an analog circuit.

The fact that the unit has a digital display does not automatically mean that it is DDS.
It could still be an analog function generator with a built in frequency meter.

You would choose a DDS function generator if you needed to specify precise frequencies.
I cannot think of too many cases where that would be a necessity for me.

 

I mainly use xtal based (or "DDS") signal generators these days.

It's very handy being able to dial an exact and stable frequency. For instance if you make a circuit that is turning on a LED when freq is >1kHz you can just set an exact 1kHz and turn the adjuster on the circuit.

And I have often debugged a PIC freq tester or measurement firmware by feeding in an exact fixed frequency and seeing what the firmware measures it as.

 

A quick thanks to those of you who offered your knowledge on this subject.

I feel more comfortable in making a decision. Thanks again - JDR04