DRIVING CIRCUIT OF SIGNAL METER

摘要

PURPOSE:To prevent the shake off and breakdown of meter, by connecting the resistance and clamper with the subsidiary electric current source turning on an electric current in proportion to the amplitude of input signal in parallel and constituting so as to fetch the output voltage from this connecting point. CONSTITUTION:A clamper 9 is added to the connecting point of an electric current source 1 subordinated to the intensity of input signal and its load resistance 8 in driving circuit of signal meter and driving voltage of a signal meter 4 is output by an emitter follower transistor 5. When an electric current I is increased by growing the input signal intense and an input voltage for the signal meter drive becomes a clamp voltage V4 or more, this input voltage is clamped at the voltage V4 by the clamper 9.By such a constitution, an excess current is not turned on the signal meter and shake off of pointer or breakdown of the meter, is prevented because of keeping drive saturated voltage of the signal meter constant.