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This is related to an earlier question of mine, but I have a different follow-up question that I wanted to make a new post for.

I'm trying to understand more about how the below circuit works, specifically the amplifier:

Taken from here with some extra details added. EDIT: Was able to find the source document here, in case that's useful to anybody.

I've tried implementing something similar with an instrumentation amp, but was told that an opamp would be a much better choice. However, I'm not totally clear about how the opamp is functioning in this context. This doesn't appear to be set up like a difference amplifier with gain-limiting feedback resistors, and it was suggested that large gain is actually beneficial here. So here's what I don't understand:

• Is this opamp configured to act as a comparator here? I.e., is the amplifier output primarily going to be saturated near 5V or ground most of the time, and avoid intermediate output voltages?

• If it's acting as a comparator, what happens when the bridge is balanced? The thermistor should be held at an elevated temp when this happens, so would we essentially see a square wave at the opamp output?

• If this isn't acting as a comparator, how is the gain being set?

Sorry for what might be a simple misunderstanding - I'm just having a hard time wrapping my head around the intended operation as I'm used to simpler opamp circuits.

This is related to an earlier question of mine, but I have a different follow-up question that I wanted to make a new post for.

I'm trying to understand more about how the below circuit works, specifically the amplifier:

Taken from here with some extra details added. EDIT: Was able to find the source document here, in case that's useful to anybody.

I've tried implementing something similar with an instrumentation amp, but was told that an opamp would be a much better choice. However, I'm not totally clear about how the opamp is functioning in this context. This doesn't appear to be set up like a difference amplifier with gain-limiting feedback resistors, and it was suggested that large gain is actually beneficial here. So here's what I don't understand:

• Is this opamp configured to act as a comparator here? I.e., is the amplifier output primarily going to be saturated near 5V or ground most of the time, and avoid intermediate output voltages?

• If it's acting as a comparator, what happens when the bridge is balanced? The thermistor should be held at an elevated temp when this happens, so would we essentially see a square wave at the opamp output?

• If this isn't acting as a comparator, how is the gain being set?

Sorry for what might be a simple misunderstanding - I'm just having a hard time wrapping my head around the intended operation as I'm used to simpler opamp circuits.

TLV2434 data sheet

2N2222 data sheet of sorts.

This is related to an earlier question of mine, but I have a different follow-up question that I wanted to make a new post for.

I'm trying to understand more about how the below circuit works, specifically the amplifier:

Taken from here with some extra details added. I've been looking for Schiretz (2012) but wasn't able to locate that text, even through a university library, so I wasn't able to find much more information.

I've tried implementing something similar with an instrumentation amp, but was told that an opamp would be a much better choice. However, I'm not totally clear about how the opamp is functioning in this context. This doesn't appear to be set up like a difference amplifier with gain-limiting feedback resistors, and it was suggested that large gain is actually beneficial here. So here's what I don't understand:

• Is this opamp configured to act as a comparator here? I.e., is the amplifier output primarily going to be saturated near 5V or ground most of the time, and avoid intermediate output voltages?

• If it's acting as a comparator, what happens when the bridge is balanced? The thermistor should be held at an elevated temp when this happens, so would we essentially see a square wave at the opamp output?

• If this isn't acting as a comparator, how is the gain being set?

Sorry for what might be a simple misunderstanding - I'm just having a hard time wrapping my head around the intended operation as I'm used to simpler opamp circuits.

This is related to an earlier question of mine, but I have a different follow-up question that I wanted to make a new post for.

I'm trying to understand more about how the below circuit works, specifically the amplifier:

Taken from here with some extra details added. EDIT: Was able to find the source document here, in case that's useful to anybody.

I've tried implementing something similar with an instrumentation amp, but was told that an opamp would be a much better choice. However, I'm not totally clear about how the opamp is functioning in this context. This doesn't appear to be set up like a difference amplifier with gain-limiting feedback resistors, and it was suggested that large gain is actually beneficial here. So here's what I don't understand:

• Is this opamp configured to act as a comparator here? I.e., is the amplifier output primarily going to be saturated near 5V or ground most of the time, and avoid intermediate output voltages?

• If it's acting as a comparator, what happens when the bridge is balanced? The thermistor should be held at an elevated temp when this happens, so would we essentially see a square wave at the opamp output?

• If this isn't acting as a comparator, how is the gain being set?

Sorry for what might be a simple misunderstanding - I'm just having a hard time wrapping my head around the intended operation as I'm used to simpler opamp circuits.

This is related to an earlier question, but I have a different follow-up question that I wanted to make a new post for.

I'm trying to understand more about how the below circuit works, specifically the amplifier:

Taken from here with some extra details added. I've been looking for Schiretz (2012) but wasn't able to locate that text, even through a university library, so I wasn't able to find much more information.

I've tried implementing something similar with an instrumentation amp, but was told that an opamp would be a much better choice. However, I'm not totally clear about how the opamp is functioning in this context. This doesn't appear to be set up like a difference amplifier with gain-limiting feedback resistors, and it was suggested that large gain is actually beneficial here. So here's what I don't understand:

• Is this opamp configured to act as a comparator here? I.e., is the amplifier output primarily going to be saturated near 5V or ground most of the time, and avoid intermediate output voltages?

• If it's acting as a comparator, what happens when the bridge is balanced? The thermistor should be held at an elevated temp when this happens, so would we essentially see a square wave at the opamp output?

• If this isn't acting as a comparator, how is the gain being set?

Sorry for what might be a simple misunderstanding - I'm just having a hard time wrapping my head around the intended operation as I'm used to simpler opamp circuits.

This is related to an earlier question of mine, but I have a different follow-up question that I wanted to make a new post for.

I'm trying to understand more about how the below circuit works, specifically the amplifier:

Taken from here with some extra details added. I've been looking for Schiretz (2012) but wasn't able to locate that text, even through a university library, so I wasn't able to find much more information.

I've tried implementing something similar with an instrumentation amp, but was told that an opamp would be a much better choice. However, I'm not totally clear about how the opamp is functioning in this context. This doesn't appear to be set up like a difference amplifier with gain-limiting feedback resistors, and it was suggested that large gain is actually beneficial here. So here's what I don't understand:

• Is this opamp configured to act as a comparator here? I.e., is the amplifier output primarily going to be saturated near 5V or ground most of the time, and avoid intermediate output voltages?

• If it's acting as a comparator, what happens when the bridge is balanced? The thermistor should be held at an elevated temp when this happens, so would we essentially see a square wave at the opamp output?

• If this isn't acting as a comparator, how is the gain being set?

Sorry for what might be a simple misunderstanding - I'm just having a hard time wrapping my head around the intended operation as I'm used to simpler opamp circuits.