Electronics > Beginners
LM741 connections with signal generator
rstofer:
Do understand that the voltage swing might be as low as +-10V given +-15V supply. In other words, depending on the load, the OA can only get to 5V from the rails. So, you might have a situation where your output swing can only be +-4V.
See "Output Voltage Swing" on page 5
http://www.ti.com/lit/ds/symlink/lm741.pdf
w2aew did a great video on op amps and what happens when the signal gets to the limit of swing:
Around 9:00, he shows on a scope how the output clamps.
The "Input Voltage Range" (also on page 5) is also limited to 3V away from the rails so +-6V if you are using a pair of 9V batteries.
alsetalokin4017:
Note that R2 and R1 in these schematics form a voltage divider for the inverting input to the op-amp. It is fun to substitute other "Voltage dividers" for these two resistors -- like a potentiometer, with the wiper going to the inverting input, or a pair of Light-Dependent Resistors instead of the fixed resistors.
Also there are a bunch of op amps that have the same pinout. It is fun to set up a circuit on the breadboard and then pop in different opamps, or even same part number parts from different manufacturers, and see how differently they behave.
Gazmon:
--- Quote from: Zero999 on March 26, 2019, 08:33:05 pm ---
--- Quote from: Gazmon on March 26, 2019, 07:09:35 pm ---Can I use 2 x 9v battery’s connected togeather to get a positive/negative voltage of 18v to power the LM741?
Will 18v be ok ?
--- End quote ---
Yes.
--- End quote ---
I need to take the battery ground connection to the ground connection (0v) on my breadboard setup yes
rstofer:
Yes, ground is as you shown it. Now, connect the signal generator ground to this point.
Use the voltage follower circuit you provided in Reply 3 with, say, 10k resistors. Keep the gain to 1 until round two of your experiments.
Keep your signal generator output low at about 1V peak to peak until round two. I would put a 10k resistor in series with the signal to protect the op amp. If my generator didn't swing around 0V I might have to put a capacitor in series with the signal. Anything around 1 ufd up to 100 ufd will probably work at audio frequencies.
Remember, you can't get within 5V of the rails so your maximum signal swing is +-4V. It's also worth noting, your batteries are a little low as the minimum supply voltage is +-10V for all variants.
Here is the datasheet:
http://www.ti.com/lit/ds/symlink/lm741.pdf
Every number is important. Note that there are 3 devices: LM741, LM741A and LM741C and they have different capabilities in terms of output voltage swing. Your device should be marked but if it isn't, I would take the worst case of the 3 devices.
At some point, you may want to build up a dual 15V power supply. I didn't need it but I just built:
https://www.jameco.com/z/JE215-Dual-Output-Adjustable-Linear-Regulated-Power-Supply-Kit_20626.html
Gazmon:
Hi
I have attached my scope reading as they appear with my sigen input, why is my amplitude not correct to my outputted sigen signal
Just outputting a triangle waveform and cycling through the others
I’m connected as an non inverting I think , positive sigen connected to the -
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