Signal generator - max current draw

ApacheKid

Joined Jan 12, 2015
1,269
I have an SDG1025 from Siglen.

I want to know what is the max current the outputs can sink, when driving say a small LED/resistor combo.

This is evident in the specs - am I missing something?

(It does mention that O/P can go up to 10 V and says "50 Ohm" so does that mean it could sink up to 200 mA (at that voltage) and be fine?)

Thanks

Audioguru again

Joined Oct 21, 2019
6,162
Its spec's say 3Vp-p max (1.5V peak) into 50 ohms which is 1.5V/50 ohms= 30mA.

Papabravo

Joined Feb 24, 2006
20,394
I have an SDG1025 from Siglen.

I want to know what is the max current the outputs can sink, when driving say a small LED/resistor combo.

This is evident in the specs - am I missing something?

(It does mention that O/P can go up to 10 V and says "50 Ohm" so does that mean it could sink up to 200 mA (at that voltage) and be fine?)

Thanks
That specification is more relevant to driving an AC load which is characterized by an impedance with a magnitude of 50 Ω.
For example an impedance of 35.35 + j35.35 has an impedance of 50 Ω with equal real and imaginary parts. The peak current in the real part of that impedance at 10 V is 0.283 Amperes.
This is not a continuous current DC specification. You can experiment but do so in a safe and controlled fashion.
25 mA is the specification on my signal generator.

Last edited:

jjw

Joined Dec 24, 2013
816
Its spec's say 3Vp-p max (1.5V peak) into 50 ohms which is 1.5V/50 ohms= 30mA.
CH1 output is max 10Vpp, offset +-5V -> for example 0 to 10V or 0 to -10V

ApacheKid

Joined Jan 12, 2015
1,269
That specification is more relevant to driving an AC load which is characterized by an impedance with a magnitude of 50 Ω.
For example an impedance of 35.35 + j35.35 has an impedance of 50 Ω with equal real and imaginary parts. The peak current in the real part of that impedance at 10 V is 0.283 Amperes.
This is not a continuous current DC specification. You can experiment but do so in a safe and controlled fashion.
25 mA is the specification on my signal generator.
Yes they didn't specify the nature of the 50 Ohm load, of course it could be a reactive load but they don't mention a power factor. It would help if there was a bit more clarity in the document.

dl324

Joined Mar 30, 2015
15,838
am I missing something?
That's not what signal generators were intended to do. If you want to drive a significant load, just use an appropriate buffer to drive it.

KeithWalker

Joined Jul 10, 2017
2,872
The output impedance is 50 ohms. That means that when the output is connected to a 50 ohm load, the specified output voltage will be across the load. If you measure the output with an instrument that has a high input impedance, the output voltage will be twice the specified loaded output.