Cable for Elenco SG-9000

[airrace]

Hello all...I just bought an Elenco SG-9000 signal generator with no output cable. I have not received the unit yet and don't know the output impedance. I know that the cable is a BNC that needs to be matched to the impedance at the generator end. What is on the other end of the cable to input the signal into the circuit? Is it possible to buy a replacement cable?

THANKS!!!! Steve in Albuquerque

 

[alfa88]

I was going to tell you to look it up but when I saw the manual it looks like they don't want to tell you. There is a section where they mention hooking up a 50 to 200 Ohm resistor. It's been my experience that sig. gen. outputs are 50 Ohms. A replacement test cable can be had most likely from the manufacturer. electronics parts distributor. EBay or just get parts from Radio Shack and DIY. Look for 50 Ohm coax.

 

[airrace]

Thanks for the help

I was going to tell you to look it up but when I saw the manual it looks like they don't want to tell you. There is a section where they mention hooking up a 50 to 200 Ohm resistor. It's been my experience that sig. gen. outputs are 50 Ohms. A replacement test cable can be had most likely from the manufacturer. electronics parts distributor. EBay or just get parts from Radio Shack and DIY. Look for 50 Ohm coax.

Thanks for the idea. If I buy a cable from Radio Shack, is the length critical to keep it at 50 ohms? Can you tell me what is on the "business end" (at the test point) to inject the signal into the circuit...ie: probe point of some kind? Thanks!!!

 

[alfa88]

The 50 ohms I speak of is the impedance of the cable. RG-58U is fairly common 50 ohm coax. As for length, just keep it reasonable. Around 3 feet (1meter) . For the test lead side use flexible wire, say 4" (10cm). I like an alligator clip for ground and an easy hook type clip for the signal. Here's a little primer on coax cable:
http://www.dkdinst.com/articles/50ohmnotes.html

 

[daddles]

It is likely a 50 ohm output impedance. You can find RG-58 coax cables pretty cheap on the web. One place I buy things from is All Electronics. I use lots of coax cables; the sizes I use the most are half meter and 1 meter. At my bench, the half meter cables probably get used the most. 30 years ago or so I standardized on using coax cables for making measurements, connecting power supplies, etc. and they have worked well for my needs. You'll probably want to buy a selection of adapters too -- see the attached photo of the ones I use frequently.