Hi

I need to buy a function generator for a test. The test requires a duty cycle of 90%. Most of the function generators have a that I looked at have a maximum rating of 85 %. The function generator at my disposable is a 4001A B&K Precision FG. Looking over the data sheet does not specify a duty cycle maximum.

Regards

 

Presumably the 'function' is a simple rectangular wave-form?
How accurate must the timing be?
What frequency and amplitude?

 

Presumably the 'function' is a simple rectangular wave-form?
How accurate must the timing be?
What frequency and amplitude?

The frequency can be as low as 1 Hz. The amplitude is 10 Vp.
Accuracy of timing is not important. Just the duty cycle is specified.

 

Max frequency? It would seem you should be able to do that with a processor,

Here's the page from a PICAXE processor. It's programmable in BASIC. http://www.picaxe.com/BASIC-Commands/Digital-InputOutput/pwmout/ Check HWPIN too.

 

The 4001A B&K Precision FG will not apparently do a 90% pulse waveform.
Do you want to buy a generator or build a circuit to do what you want?

Here's a simple PWM circuit that can be adjusted to a duty-cycle of above 90%.

 

This is for an ongoing test that will need to be repeated. I just surprised that a simple thing like a 90% duty cycle can't be purchased. I suppose the circuit will work if using professional test equipment cannot work. What about using a Aurduino kit with an amplifier. Could that not get the same result?

 

I suppose the circuit will work if using professional test equipment cannot work.

There is professional equipment that will work to generate the signals you need, just not the B&K model you have.
For example this B&K 4030 pulse generator has independent adjustment of pulse width and frequency, which should allow you to get any duty-cycle you need.