Current limiter with current measuring resistor - voltage drop is applied to amplifying component with constant bias

摘要

The circuitry provides a constant current supply maintaining great accuracy over a wide temperature range. The amplifying component consists of two transistors (T1, T2) and a base resistor (R1) for the control transistor (T2). The transistor base-emitter voltages are connected in opposite senses for the voltage drop across the current measuring resistor (R2) comparison with the reference voltage (UZD), so that when the two voltages are equal, voltage drop across the resistor (R2) is equal to the reference voltage (UZD). The currents (V1 & IV2) are switched to the users (V1 & V2) by means of transistors (T3 & T6). At a certain point (5) a reference potential can be tapped for further current sources. The bias of the transistors (T3 & T6) regulates the users (V1 & V2).