Lineariser for static characteristics of limiting amplifier - utilises hall effect detector in variable speed motor load circuit to provide feedback voltage

摘要

The static characteristics of limiting amplifiers are linearised so that the output voltage is independent of the current circulating in the load and from variations in the supply voltage. This is achieved by sensing the sign of the current in the load esp. that applied to a variable speed motor, to provide a feedback signal. A Hall effect detector (2) inserted in the supply circuit for the load (1) delivers a voltage (V) of the same sign as the detected current (I). A comparator (3) produces a voltage with a constant offset and with the same sign as the detected current. This voltage is summed with the control voltage (E) and the resultant is applied as the numerator (N) to an analogue divider circuit (5). The denominator (D) input is connected to the supply line (Ub). The divider output is amplified (6) to provide a linearised input for the load circuit.