If your function generator has a 50 ohm output resistance, it can drive an LED directly.
You can use a transistor, if you still want to.

Hey. I saw the circuit you uploaded. I also want to make an LED flash only by ussing a generator ? Is it possible ? If I try only the first part of the image you uploaded can I achieve that ?
Do I need a power supply ??
Thank you very much for your answer .

Hyjacking someone elses thread is not allowed, Now you have a thread of your own.

This was split from

https://forum.allaboutcircuits.com/threads/blinking-led-project.76868/#post-1195148

 

I also want to make an LED flash only by ussing a generator ? Is it possible ? ...
Do I need a power supply ??

An LED is versatile but is easily damaged by too much current. So in most applications there are other components to prevent excessive current. It could be as simple as using a battery with so little capacity that it cannot overpower the LED. It could be a resistor in series with the LED.

The current-limiting circuitry you need depends on the power supply you want to use.

 

If you want I could draw a schematic I think migh work?



This ought to do it I thought about putting a large capaxitor on the input lin because any DC On the signal source will stop the circuit from working. Q1 is not critical It can b a TIP100 or similar.

 

Hi Wendy. Not PNP-darlington! but NPN.
See

 

I also want to make an LED flash only by ussing a generator ? Is it possible ?

If the signal generator can provide enough current, you only need to add a resistor.


But signal generators aren't usually used in this manner. It's more common for a circuit to have it's own power source and the signal generator provides input to a fairly high impedance, or a matched impedance (e.g. 50 ohms).

 

The current-limiting circuitry you need depends on the power supply you want to use.

Just reinforcing my point.

There's nothing more we can say without details.