This circuit changes the voltage to current, can provide dc current characteristics and AC so-so Circuit consists of 3 op-amps, 2 transistors is moderate. Passive devices and only a little.
This circuit with grounded. load, it controls the rate Vout / Vin easily, it also has a wide area ranging from about 1 uA output rate of resistance to the flow of the output transistor. It has a high output impedance 50 Meg Ohm is a high accuracy, stability and low noise.
The IC op amp (IC1) acts to change the input voltage.
The IC op amp to the second (IC2) in conjunction with transistor changes the voltage.
For (IC3) is a voltage follower reduce the impact of various sensing current with output currents.
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