pc as tone generator

H Folks,

If i'm generating a sine tone from my pc, what is the best method of infecting it into a circuit?  Are there specific leads I can buy which convert from the headphone jack?

burglar said:

H Folks,

If i'm generating a sine tone from my pc, what is the best method of infecting it into a circuit?  Are there specific leads I can buy which convert from the headphone jack?

Click to expand...

I think you need several different cables in order to cater for all the different needs.
You'll need adapters for the most common audio connectors (XLR, jack and RCA).
I suggest you start with a standard cable going from male 3.5 jack to two 1/4" mono male jacks. Then you can use 1/4"-to-XLR, 1/4"-to-RCA.
Now if you want to use the good old "signal-tracer" method, you need to make an adapter with a DC protection cap (typically 0.1uF with high-voltage rating, 250 or 400V), a protection resistor (about 10k should cover most needs) and ideally a BNC socket that would allow you to use a standard o'scope probe for reaching the innards. Alternatively, or better, in addition, you could have a pair of 4mm banana sockets, so you could use  standard multimeter cords.

this is for the u87 project.  I need to take a 1k sine wave and inject to the leg of a resistor.....

For TH resistors the fast proves usually as the digital analysers is a nice option. So, the mini plug, a cap (or two for better "insulation") and those proves would make what you need for this task.

JS

A mini jack to Alligator clips would be quite useful also,
I did a cable like that to use when I send a signal from my Mac.

Sorry guys, i don't understand what you mean here.  Could you please explain again the quickest way to output a 1k sine wave from my laptop and inject it into a mic via the leg of a resistor.?

burglar said:

Sorry guys, i don't understand what you mean here.  Could you please explain again the quickest way to output a 1k sine wave from my laptop and inject it into a mic via the leg of a resistor.?

Click to expand...

Assuming your laptop has the standard ⅛" TRS jack for stereo out, get one of those ⅛" TRS-to-dual-RCA-plug cables. Choose a channel, left or right. Solder one leg of the resistor to the center pin of the chosen channel's plug. Solder a stiff wire to the plug's ground ring. That's your injection probe. Connect cable ground to circuit ground somehow. Use the free end of the resistor to inject the signal where you want.
Alligator clips help.

If you will be analyze microphone output (for bias setup)  on conventional oscilloscope, use the highest possible sample rate on your sound card test tone output.