Attach speaker to a Function Generator - Page 1
Forum section: electronics / beginners

author: staze
author_rank: Frequent Contributor
timestamp: May 23, 2013, 07:48:47 am
content: So, just futzing around, I figured (probably like most people) I could attach a simple speaker to my Function Generator (FG) and test both frequency response, and heck, my hearing thresholds. =)I guess my question is, the speaker is 4R impedance. The FG is expecting at least 50R. So I should just be able to throw a couple 100R resistors (in parallel) in series with the speaker and get ~54R, which should keep the FG from being overloaded too much, yes, or is that not really a worry with an FG?Thanks!

author: Balaur
author_rank: Unknown
timestamp: May 23, 2013, 10:13:57 am
content: You'll be hard pressed to find a simple speaker with a frequency response good enough for any kind of hearing checking and so on.Ideally, you'll need a good (monitoring) loudspeaker system driven by an amplifier.Better, just use a good headphone (32 ohm+, 16 ohm also work) and drive them directly with your FG. Please take care of the signal levels and use the -20dB feature, otherwise you will break your headphones.You can find headphones with a good frequency response for not so much.

author: DaveW
author_rank: Frequent Contributor
timestamp: May 23, 2013, 11:02:20 am
content: Assuming we're talking about a bench function generator, I think you'll find that it has 50 ohms in series with the output already. You should be able to get something out of your speaker hooking it up directly

author: Paul Price
author_rank: Super Contributor
timestamp: May 23, 2013, 11:56:11 am
content: Use am amplified speaker system from a desktop computer speaker system and use the input from PC plug to feed the signal gen.Or else if you can handle the do it yourself hi-tech way see below:I have received more than a pair of complementary comments about how well this simple circuit works.

author: Unknown
author_rank: Unknown
timestamp: May 23, 2013, 12:44:26 pm
content: Rather than doing that to your FG, put headphones in computer google audio tone generator, and listen to there's. here's a linkhttp://www.nch.com.au/tonegen/index.html?gclid=CJfasL6grLcCFZMftAodun0AnAfg

author: Rufus
author_rank: Super Contributor
timestamp: May 23, 2013, 01:23:49 pm
content: Quote from: staze on May 23, 2013, 07:48:47 amIt would have to be a crappy FG for driving into a short circuit to do any damage.

author: staze
author_rank: Frequent Contributor
timestamp: May 23, 2013, 03:37:44 pm
content: Quote from: Rufus on May 23, 2013, 01:23:49 pmIt's a TTi TG1000, it's quite nice. But it does have a note in the manual saying it can handle 60 seconds of short circuit. Which makes me think after that 90 seconds, something will likely happen."To maintain waveform integrity only 50? cable should be used and the receiving end should be terminated with a 50? load. It can tolerate a short circuit for 60 seconds."

author: staze
author_rank: Frequent Contributor
timestamp: May 23, 2013, 03:38:50 pm
content: Quote from: Telequipment on May 23, 2013, 12:44:26 pmYeah, I have that software. It's quite useful, but there's something a bit more "fun" dialing up the frequency with the FG. =)

author: Unknown
author_rank: Unknown
timestamp: May 23, 2013, 03:48:05 pm
content: Quote from: staze on May 23, 2013, 03:38:50 pmOK, don't damage your ear drums

author: GK
author_rank: Super Contributor
timestamp: May 24, 2013, 11:36:46 pm
content: Most headphones will have significant aberrations in frequency response when driven by the high output impedance of a function generator (generally either/or 50/600 ohms).