A voltmeter for measuring atmospheric or other voltages eliminates the dead band without application of high voltages or radioactive isotopes to increase conductivity in the region of the probe. A vacuum tube is operated at substantially reduced conduction in order to achieve high sensitivity and eliminate passive components in the input circuit. A voltage is developed to produce meter indication or control charging or charge-neutralizing circuits. In the preferred embodiment, a meter scale is calibrated to indicate the presence of atmospheric charges of particular interest to anglers. Naturally occurring electrical currents are known to stimulate the feeding of fish.