Measuring arrangement for measuring an effective value of an ac voltage in a handheld power tool

Abstract

The hand-held power tool according to the invention has a measuring system for determining an effective value of an alternating voltage (U), which is fed via an external conductor (L) with respect to a neutral conductor (N). A regulated direct voltage source (25) has a power supply potential (Vcc), which is referenced to the neutral conductor (N). The direct voltage source (25) adjusts the potential of a ground (23) against the power supply potential (Vcc). A voltmeter (26) is supplied with power by the direct voltage source (25). A voltage divider is suspended between the power supply potential (Vcc) and ground (23). There is a first resistance value (R1) from the power supply potential (Vcc) to a tap and there is a second resistance value (R2) from the top to ground (23). A voltmeter (26) has a measurement range (Mb) and its measurement input is connected to the top (27). A measurement line connects the tap to the external conductor (L). The first resistance value (R1) is selected to be lower than the second resistance value (R2), such that the mean voltage value on the tap is equal to the center of the measurement range (Mb) for one period of the alternating voltage (U).

Dependencies are inferred from the claim text.