Solid State Magnetic Field Sensor With Zero Power Consumption

This paper introduces a new type of solid-state magnetic field sensor that is similar in size to a Hall effect sensor and that offers a sensitivity that is approximately an order of magnitude better than a Hall effect sensor. The significant advantage of the new sensor, however, is that it consumes no power. The sensor consists of a radioactive β-particle source and a silicon p-n junction. If no magnetic field is applied, the β particles enter the p-n junction and generate a steady dc voltage. Under the influence of a magnetic field, however, the β particles (or secondary electrons generated therefrom) follow a curved path and miss the p-n junction, and the magnitude of the output voltage drops. The new sensor will be very advantageous in battery-powered consumer products applications because it consumes no power.