Abstract: The invention relates to an integrated transistor circuit comprising a transistor (Q1) of which the collector is connected to an input of a circuit (S) and between the base and collector of which an antisaturation diode (D1) is connected. According to the invention a further current branch is provided between the base and the emitter and includes a series circuit of a diode (D2) and a resistor (R1). As a result, a leakage current flowing in reverse direction into the antisaturation diode (D1) flows via the diode (D2) and the resistor (R1) and not via the emitter-base path of the transistor (Q1) and consequently amplification of the leakage current is prevented.

Abstract: A voltage follower circuit comprising an input (10) for applying an input voltage and an output (20) for emitting an output voltage dependent on the input voltage includes a first current mirror circuit (Q1, Q3) having an input transistor (Q1) and an output transistor (Q3), the current flowing through the input transistor (Q1) depending on the input voltage and the output voltage being generated in dependence upon the current through the output transistor (Q3). Associated with the output transistor (Q3) of the first current mirror circuit (Q1, Q3) is a further input transistor (Q4) which with said output transistor (Q3) forms a second current mirror circuit (Q3, Q4). In the collector line of the further input transistor (Q4) a constant current source (K2) is disposed which impresses a constant current onto the second current mirror circuit (Q4, Q3).

Abstract: A driver circuit for switching on lamps with low cold resistance. The circuit includes a power transistor (T5) of which the collector-emitter path is connected to the lamp (12) in a series circuit which lies between a positive terminal and a ground terminal of a supply voltage source. The circuit further includes an RC member comprising a resistor (R1) which is connected on one side to the ground terminal and a capacitor (C) which is connected in series with the resistor and on one side to the positive terminal of the supply voltage source. A comparator (38) compares the voltage at the resistor (R1) with the voltage at the collector of the power transistor (T5) and furnishes at an output a blocking signal for the power transistor (T5) when the voltage at the resistor (R1) is more negative than the voltage at the collector. A limiting member (T4) limits the voltage at the resistor (R1) to a voltage value lying above the saturation voltage of the power transistor (T5).