My op-amp design is a bit shady these days - like 40 years ago!

I have a 741 op-amp and I know how to calculate the gain etc, but what I am shady on is choice of resistor values. That is, benefits for going high values Vs lower values.

Now I know that a 1k input resistor and a 3k feedback resistor will give me a DC gain of 3X. So will 10k and 30k resistors and 100k and 300k resistors.

What are the benefits/advantages/disadvantages of choice of values - low Vs high?

OK, blind leading the blind here, but

741, well suited to your 40-year-old experience. I think there are much better OAs around these days (don't ask me what, based on what an Analogue engineer mate said to me a while back when he saw one of my designs using a 741).

Within reason I think the only difference between the resistor values used is the input impedance you present to the circuit being amplified. So normally I'd say go high.

Rob

For 'normal' op amp use that is fine - where it gets a bit more complex is when, for example, you want to use the op amp as a high or low pass filter and you have to match capacitor reactance (Impedance) to the input or the feed back resistor to 'shape' the filter frequency response.

d.m.