Square to triangular waves generator (Using LM555CM and Op_Amp 741)

[laurynasburba]

Hello, I have some troubles understanding this circuit. I have to describe functions of U1, (R1 and C2) together.
I tried to do some researches at google, but nothing came up and now I am struggling, maybe here someone could help me?
If picture is not so bright, just tell and I will fix it!
P.S. U1 is LM555CM and R1 is 50kΩ resistor and C2 is 100nF. I know purpose of the circuit, but I don't know how to explain how components cooperate?

 

[ericgibbs]

hi,
As its home work just a clue.

The 555 is configured as an Astable, a square wave generator, the 741 is configured as an Integrator.

Look up 555 Astable and OPA Integrator then post your explanation of how it works, we will then help you.

 

[laurynasburba]

Ok, thank you for a clue. Correct me if I am wrong, U1 is a square wave generator and R1&C2 are keeping it an Astable?

 

[laurynasburba]

R1 is giving the frequency that we needed and with C2 you choosing the range of frequency.. am I right?

 

[ericgibbs]

R1 is giving the frequency that we needed and with C2 you choosing the range of frequency.. am I right?

hi,
You are almost right.
The two R1 and R2 resistors to the capacitor control the charge and discharge time of the capacitor Ct.

The 555 detects the levels of the voltage on the capacitor during its charge and discharge cycle, the 555 output [pin3] is switched high and low at the detected levels. This high/low sequence is a square wave.. If you changed the values of the resistors and/or the capacitor the charge/discharge times would change and the so would the output square wave.

In this image Ra=R1 and Rb=R2.

You should now be able to work out the rest yourself.