autoranger

Although designed in the first in-stance for use with the universal digital meter which was published in Elektor 45, this circuit for an auto-matic range switch (for DC input voltages) can also be used with other meters. Input voltages between O and 1 V are fed directly to the output, voltages between 1 V and 10 V are attenuated by a factor of 10, whilst voltages between 10 and 100 V are attenuated by a factor of 100. Thus the output voltage fed to the meter will always lie between O and 1 V, regardless of the amplitude of the in-put voltage.