Designing a functional function generator using op-amps

Thread Starter

MateoEV

Joined May 26, 2023
22
Find an op amp in your country (wherever that is) that has better frequency response and slew-rate characteristics.
Otherwise you won't be able to meet the specified required circuit operating characteristics.
Thanks, I'll have to go searching.
 

schmitt trigger

Joined Jul 12, 2010
2,090
Find the TL072, it is almost as ubiquitous and cheap as the LM741, but it has 5 times the slew rate (I am quoting from memory, check the datasheet).
Additionally, as it has a JFET input, it has orders of magnitude higher input impedance, which will allow you more freedom in choosing the input values.
 

Audioguru again

Joined Oct 21, 2019
6,826
The TL072 is a dual opamp. A TL071 is the single opamp with the same pin numbers as an antique LM741.
The LM741 has slew rate problems at high levels above 9kHz. Then it cannot produce a half-decent squarewave above 900Hz.
The TL071 and most modern opamps have a slew rate that works well up to 100kHz.

The LM741 is a copy of the original UA741 that was designed 55 years ago. They have many problems and should be buried.
 

crutschow

Joined Mar 14, 2008
38,512
The LM741 is a copy of the original UA741 that was designed 55 years ago. They have many problems
Which makes it a good learning tool for beginners.
The frequency response, slew rate, offset, and voltage limitations are rather magnified with the 741 to make the newbie aware that they are there to some degree with all op amps.
 

dl324

Joined Mar 30, 2015
18,329
Find the TL072, it is almost as ubiquitous and cheap as the LM741
From post #1, LM741 was specified as a requirement. Teachers often use this opamp to reinforce the nature of nonideal devices.

Though in its heyday, it was the greatest thing since sliced bread.
The primary requirement is to generate square and triangle waves (varying their frequencies through potentiometers) using LM-741 IC's.
 

Thread Starter

MateoEV

Joined May 26, 2023
22
Hello everyone, thank you for your help. In the end I followed your advice and changed the op-amps to TL071, since our professor approved it. I also incremented the lowest load value on the square generator section of the circuit and changed some of the capacitance values. In the end the circuit worked between frequencies around 1 kHz and 3 kHz without any major trouble. It was although necessary to add a passive high-pass filter at the triangle wave output in order to solve some DC offset problem, as well as an extra pair of inverting operational amplifiers in order to control the signals amplitude. Again, I thank you all for your responses, I certainly learnt some useful stuff designing this circuit.
 
Top