The present invention is based on the finding that a capacitance can be measured precisely and efficiently when, in a delta-sigma modulator having an operational amplifier, a first capacitor connectable to an input of the operational amplifier, and a second capacitor in a feedback branch of the operational amplifier, a reference signal source is connectable to the first capacitor, wherein the first or second capacitor may represent a capacitance to be measured. Due to the fact that, in contrast to what is conventional, no input quantity is measured and digitalized at the input of the delta-sigma modulator, but instead a defined reference signal source is coupled at the input and a device of the delta-sigma modulator itself represents the measuring quantity, an extremely compact circuit is provided allowing capacitances to be measured quickly and reliably, the measuring result being additionally made available in a digital form.