Darlington Q1/Q2 feeds 0-Ω load, V_LOAD, with a current. R2, R5, R4 and C2 establish stability and should be checked in assembled circuits. R1 establishes the minimum Q1 DC bias

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Other Materials from the Main Document

• Article «A high-performance current source»
• Figure 1. A series of LM317 circuits investigated in simulation and on the test bench for suitability as a current source
• Figure 2. Darlington Q1/Q2 feeds 0-Ω load, V_LOAD, with a current. R2, R5, R4 and C2 establish stability and should be checked in assembled circuits. R1 establishes the minimum Q1 DC bias
• Figure 3. The PSRR impedances in ohms verses frequency as seen by V_LOAD for three different DC currents. Higher impedances are associated with more nearly ideal current sources. The dots on the curves represent simulation measurements
• Figure 4. The Impedance in ohms seen by V_LOAD at three different DC currents. Higher impedances are associated with more nearly ideal current sources. The dots on the curves represent simulation measurements
• Figure 5. Transfer impedances in ohms verses frequency from V_IN to V_LOAD. The design goal is a value of 1.0000. The dots on the curves represent simulation measurements