I have been using this website for a few years now. I decided to do a degree in Electronic Engineering last year, and I am already struggling
I have attached a circuit that is part of a report I must do on a fuel level indicator. V_fuel ranges from 0 to 3V, where 3V is a full tank. OA1, OA2, and OA3 are HCT logic family op-amps (i.e. TL074). Vp=5 and Vm=-5.
I have more questions than answers about this circuit to be honest. We are only just learning this material, so it is a big step for me to absorb it all.
I'll begin with my attempt at explaining the circuit. I think that the resistors R1 to R4 will give out a stepped signal, ranging over time, from greatest voltage to least. Then they go into a summing amplifier? Which will then invert the signal too. The next op-amp I am uncertain of, I know it has a gain of 1 due to R6=R7, but I don't know what it's doing except inverting the signal? The next op-amp I believe is a comparator, that will compare V_fuel with the stepped signal. It will give out a 5V signal for when the analogue signal is closest to the step that corresponds to the binary equivalent. The diode is to make sure that a negative value never gets through? I don't know why the logic inverter is there.
I must calculate the values of R1 -> R5, the assignment says that they should give out voltages between 0V to 3.75V. I am not certain how to do this as I dont know what the op-amp is going to do. I believe the resistor network, and the next two op amps are combined to be as what is normally considered a DAC?
I must also draw graphs of points J, K, and L in a complete cycle. L should be trivial, I think J is simply the inverted steps. K back to the non-inverted steps again??
My initial thinking was that the summing amplifier is level shifting down to 0 to 3.75V and the next op amp is simply inverting the signal. Anyway, sorry about this big lump of text, but I have so many questions and very little answers; if it is too much to decipher what I mean, then if you can, please try to explain what the first two op amps are doing and why they are doing it.
I have attached a circuit that is part of a report I must do on a fuel level indicator. V_fuel ranges from 0 to 3V, where 3V is a full tank. OA1, OA2, and OA3 are HCT logic family op-amps (i.e. TL074). Vp=5 and Vm=-5.
I have more questions than answers about this circuit to be honest. We are only just learning this material, so it is a big step for me to absorb it all.
I'll begin with my attempt at explaining the circuit. I think that the resistors R1 to R4 will give out a stepped signal, ranging over time, from greatest voltage to least. Then they go into a summing amplifier? Which will then invert the signal too. The next op-amp I am uncertain of, I know it has a gain of 1 due to R6=R7, but I don't know what it's doing except inverting the signal? The next op-amp I believe is a comparator, that will compare V_fuel with the stepped signal. It will give out a 5V signal for when the analogue signal is closest to the step that corresponds to the binary equivalent. The diode is to make sure that a negative value never gets through? I don't know why the logic inverter is there.
I must calculate the values of R1 -> R5, the assignment says that they should give out voltages between 0V to 3.75V. I am not certain how to do this as I dont know what the op-amp is going to do. I believe the resistor network, and the next two op amps are combined to be as what is normally considered a DAC?
I must also draw graphs of points J, K, and L in a complete cycle. L should be trivial, I think J is simply the inverted steps. K back to the non-inverted steps again??
My initial thinking was that the summing amplifier is level shifting down to 0 to 3.75V and the next op amp is simply inverting the signal. Anyway, sorry about this big lump of text, but I have so many questions and very little answers; if it is too much to decipher what I mean, then if you can, please try to explain what the first two op amps are doing and why they are doing it.
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