A video amplifier, for driving a kinescope, employs two transistors of opposite conductivity arranged in a series path and further having their emitter electrodes coupled together. The amplifier is biased stabilized by a third transistor having the collector electrode coupled to the emitter connection of the two transistors and having a capacitor coupled between the collector and base electrodes. The emitter electrode of the third transistor is returned to a source of reference potential. A unidirectional current conducting device is coupled between the base electrode of the third transistor and the collector electrode of one of the series transistors. The unidirectional device is caused to conduct a signal applied thereto and occurring during a repetitive interval, to charge the capacitor to a level determined in accordance with the quiescent voltage at the collector of said one series transistor. This level and the magnitude of said capacitor is sufficient to cause the third transistor to also conduct for the absence of said signal. This maintains the collector current of said one series transistor at the value necessary to regulate the potential at the collector electrode thereof. A further transistor stage provides peaking, contrast control and blanking functions for the video amplifier, as described above, by operating on the luminance component of the composite signal for application thereto to the base electrode of the other one of said series transistors.
