Abstract: A self-directing bus amplifier and method is disclosed, which includes an input biased at a given voltage level and a tri-state amplifier with a first input terminal coupled to the biased input and an output coupled to an output bus. A field effect transistor with a gate terminal coupled to the biased input and a source terminal coupled to ground potential with a drain terminal coupled to an inhibiting input of the tri-state amplifier. The drain terminal of the field effect transistor is biased, such that when a signal is present on the input the field effect transistor turns OFF, which enables the tri-state amplifier so that the signal is passed through to the output bus.

Abstract: A D.C. controlled attenuator which is particularly useful as a D.C. controlled video attenuation circuit providing three tracking channels that can be used as a tracking contrast control in an RGB monitor includes an integrated circuit having at least six MOS field effect transistors on a common substrate, the transistors being of N-channel and P-channel type and being arranged in the three groups of two each connected in complementary symmetry. In each group the gate electrodes of the N-channel and P-channel transistors are connected together, their drain electrodes are connected together and a source of D.C. potential is connected between their source electrodes in parallel. A variable resistor is connected between the gate electrodes of the transistors of a group and the drain electrodes of those transistors providing a feed forward signal path that also preferably includes a variable inductance coil. Input signals are supplied to the gate electrodes of the transistors, and the magnitude of the D.C.