Voltage measurement and display circuit - has two linear regions and one or more precision voltage limiters to effect change of scale

摘要

The voltage is measured by a moving coil meter (3) with a series resistor (4). In parallel with this is a second resistor (2) in series with a precision voltage limiter (1). This second resistor effects a change of the scale of the measurement for voltages large enough to cause the limiter circuit to conduct. The precision limiter circuit uses three transistors driven by a resistor divider network. Temp. compensation of the transistors is provided by negative temp. coefficient resistors in their base drives. More than one change of scale can be effected in the same way.