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What is the output resistance of a BJT Wilson current mirror?
The three active components (BJT) are used to make the circuitry. The BJTs are all 2N2222, with same specifications. The pot is selected to change the current across Q2 collector which will further reflect on the Q3 collector. For the output load, a 10 Ohms resistor is being selected.
How do you calculate the resistance of a current mirror?
Figure 11.13 Small-signal circuit for finding output resistance of the Widlar source shown in figure 11.11. A test current I/x is applied at the output, and the output resistance is then RO = V x / Ix.
Which technique is used to increase output resistance of a current mirror?
Feedback-assisted current mirror Figure 3 shows a mirror using negative feedback to increase output resistance. Because of the op amp, these circuits are sometimes called gain-boosted current mirrors. Because they have relatively low compliance voltages, they also are called wide-swing current mirrors.
What are the two requirements of good current source?
There are two characteristics that define a current source in real life. One is its internal resistance and the other is its compliance voltage. The compliance voltage is the maximum voltage that the current source can supply to a load.
What is the impedance of a Wilson current mirror?
The Wilson current mirror has an output impedance that is higher by the factor , on the order of 50X. The input impedance of a current mirror is the ratio of the change in input voltage (the potential from the input terminal to ground in Figures 1 and 2) to the change in input current that causes it.
How is the output of a mirror circuit improved?
There are several options to improve the output of Current Mirror Circuit. In one of the solution one or two transistors are added over the traditional two transistors design. Construction of those circuits uses emitter follower configuration to overcome the base current mismatch of the transistors.
How is the output resistance of a Widlar circuit measured?
Therefore, To measure the output resistance of the Widlar current source, the small-signal circuit is a useful option. The below image is an equivalent small signal circuit for Widlar current source. The current Ix is applied across the circuit to measure the output resistance of the circuit. So, as per the Ohms law, the output resistance is
Who was the inventor of the current mirror circuit?
It’s all started with a challenge between two engineers, George R. Wilson and Barrie Gilbert, to make an improved current mirror circuit overnight. Needless to say that George R. Wilson won the challenge in 1967. From the name of George R. Wilson, the improved current mirror circuit designed by him is called Wilson Current Mirror Circuit.