Abstract: A portable kilovoltmeter especially suited for measuring the secondary voltage of an ignition coil includes an operational amplifier whose input is connected via an input circuit to the ignition coil secondary winding and whose output is connected via an output circuit to a galvanometer on which the secondary voltage is read. The input circuit to the operational amplifier includes a probe which forms a portion of a capacitive voltage-dividing network via which the secondary voltage is reduced in amplitude before it is supplied to the operational amplifier input. The probe includes a capacitive probe element which makes contact with the hot terminal of the ignition coil secondary and a length of high-tension, high-resistance conductor which leads from the probe element to the console containing the galvanometer and the kilovoltmeter circuitry.