A Voltage-Sensitive Switch

An investigation of the controlled dielectric breakdown of aluminum oxide films resulted in the development of a voltage-sensitive switch which may replace thyratrons and gas diodes in circuits which require single switching from a resistance in the kilomegohm range to one of the order of 1 ohm or less. Compared with a thyratron, the switch is smaller, less expensive, more resistant to shock, vibration and high-energy radiation, and requires no additional power supply. In a recent batch, all samples tested broke down between 12 and 13 volts dc. Three circuits are presented which show applications of the switch in a time delay, in a series arrangement, and in a biasing network where terminal voltage is greater than the critical breakdown voltage of the switch.