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How to create constant current source using opamp?
Iload = current flows through the load which has to be maintained constant. Isense = Current flow through the variable resistor. Now let us analyse the circuit. (1) Current flows into the input terminals is zero.
How is the current of the op amp determined?
The voltage drop over R3 will remain constant (due to the op amp), so the current can be calculated as before from ohms law: I = 1.36V/ R3. The upper limit of the current is determined by the power tolerance of R3.
How does an op-amp sink the base voltage?
The PNP transistor will sink this 1A of current and the op-amp will use this voltage drop and get the desired 1V feedback. This way, changing the input voltage will control the Base as well as the current through the shunt resistor.
How does the PNP transistor control the op-amp?
The PNP transistor will sink this 1A of current and the op-amp will use this voltage drop and get the desired 1V feedback. This way, changing the input voltage will control the Base as well as the current through the shunt resistor. Now, let’s introduce the load that has to be controlled into our circuit.
Why does the op amp increase in a constant current circuit?
Because the positive terminal is larger than the negative terminal the op-amp will become more positive and therefore increase the conduction of Q3. This increase in conduction of Q3 allows more current to flow through the load and the 0.1-ohm resistor.
Which is the constant current source in an amplifier?
We know that, the circuit which provides constant current to the load (irrespective of change in load resistance) is called as constant current source circuit. In this short post let us understand the Operational amplifier based constant current source circuit.
How to create a constant current in a circuit?
You have built a current source. This circuit achieves its constant current through the use of the Op Amp and the transistor. The first two resistors (R1 and R2) are used as a voltage divider. The voltage between them is given by