Hai friends, I need a small signal amplifier using three 741 op-amp. I am a beginner in electronics and it will be helpful for me if some one will come up with a circuit and the functional details. Thank you all.
Your request is far too vague, you need to give much more exact details - for a start what is it connecting to, what gain does it need, and what are the source and load impedances.
Hai friends, I need a small signal amplifier using three 741 op-amp. I am a beginner in electronics and it will be helpful for me if some one will come up with a circuit and the functional details. Thank you all.
But do what? - it's going to be really crap! - as Audioguru says a 741 is far too slow for class-D, and also outputs hardly any power. A completely pointless exercise!.
As a learning excersise, it would be a good circuit to expriment with. It demonstrates a lot of interesting effects without being complicated, and it can be made useful with a few very simple changes.
As a (plagiarized) homework assignment, on the other hand, it's probably giving some professor a good laugh right now...
Not when it is using an lousy old slow opamp instead of a high speed comparator.
Many class-D audio amps have a switching frequency of about 384kHz. The lousy old 741 opamp has trouble above only 9kHz. An ordinary TL07x audio opamp goes up to 100kHz.
Hai, you are right. I am beginner in electronics not studying in a college but learning all by myself out of interest in electronics. So you people are my teachers and many things do I ask do appear as home work and I need your help for that. I am attatching a circuit I intend to test on a bread board and I need to know the values of R and C so that I can make it work properly. Thanks all of you.
Hi Mojat,
A circuit needs to have specification requirements:
1) How much gain?
2) What is the cutoff frequency of this lowpass filter?
3) Is the source DC-coupled to 0V?
4) What are the supply voltages?
Your first opamp doesn't have DC negative feedback and has a DC gain of about 200,000. So it will amplify its input offset voltage of up to 10mV which might cause its output to be saturated. Then it won't work.
Do a simple filtered amplifier like this instead:
Thanks Guru, but I asked about the values of R and C. Can you give me the values or the way it should be calculated. As I told you this is only a test circuit I am doing to learn, the supply is +/-12v and I dont know about the gain and cut-off frequency.