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gladiator
Joined: 29 May 2002
Posts: 57
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 31 Aug 2004 23:47 Load resistance of inverting op-amp? |
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Hi
What will happen if the load resistor Rl in the inverting amplifier circuit is reduced to one tenth its value? Explain?
Thanks
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flatulent
Joined: 19 Jul 2002
Posts: 4879
Helped: 295
Location: Middle Earth
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| 01 Sep 2004 0:08 Re: Load resistance of inverting op-amp? |
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| Assuming that the amplifier can source the increased current, the gain will change by 10x. If the current sourcing ability is less, the output swing will be reduced.
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gladiator
Joined: 29 May 2002
Posts: 57
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| 01 Sep 2004 0:36 Re: Load resistance of inverting op-amp? |
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Hi flatulent,
Can you explain more? is the gain will be increased or dereased?
thanks
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Edward_2288
Joined: 07 Mar 2004
Posts: 72
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| 01 Sep 2004 1:52 Load resistance of inverting op-amp? |
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| this is known as the loading effect. the gain will drop.
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flatulent
Joined: 19 Jul 2002
Posts: 4879
Helped: 295
Location: Middle Earth
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| 01 Sep 2004 1:58 Re: Load resistance of inverting op-amp? |
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| I was assuming that this was the resistor from the output to the inverting input. The gain will be proportional to this resistor with the other one fixed in value. If this is a load and not a feedback resistor, the comments about output swing hold and the gain should not be affected.
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Edward_2288
Joined: 07 Mar 2004
Posts: 72
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| 02 Sep 2004 6:33 Re: Load resistance of inverting op-amp? |
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| Edward_2288 wrote: |
| this is known as the loading effect. the gain will drop. |
this holds true if there is a output buffer in the op amp.
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leo_o2
Joined: 03 Sep 2004
Posts: 356
Helped: 22
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| 03 Sep 2004 11:56 Re: Load resistance of inverting op-amp? |
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| I think the stability will be affected as well.
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ykishore
Joined: 02 Sep 2004
Posts: 53
Location: india
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| 04 Sep 2004 13:00 Re: Load resistance of inverting op-amp? |
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Can the one who has posted the reply above elucidate the answer in detail?
As far as my knowledge is concened the gain of an opamp inverter is given by
-R2/R1. If the value of R1 is made one tenth then I think that the voltage gain increases ten times.
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