Square signal from function generator have no straight edges

[samewings]

Hello, everyone!

In my task I need to visualize charging and discharging of capasitor. I have to use a scheme on attached picture to supply the capasitor, because I'm going to replace it with thermoresistor, that need some exact current level. I'm using a square signal from function generator, as a supply. But when I built my scheme on the prototyping board and connect generator, edges of square signal become nonstraight and there is no DC offset that I've set.

Can anybody help me to find out what's the problem?

Thank You in advance.

[Zach J · Accepted solution]

Hello samewings,

I have taken a little time and studied your circuit diagram.  From your oscilloscope readings, it appears that you have done well to capture the charging and discharging response of a capacitor already.  For your reference, you can compare your oscilloscope readings to the document I have provided below.  You will notice that your square wave corners are rounded just like the charging and discharging curves that can be seen when charging and discharging a capacitor.  A capacitor charges and discharges over time.  Because of this, the voltage you are reading across your circuit will show this time-dependent curve on the edges of your square wave.  

Charging & Discharging a Capacitor

[samewings]

A problem has dissapeared. Sorry for bothering, it was my fail. Thank You for reply=)