Fail-safe element using thin film parametron

In addition to a memory apparatus, one of the applications of thin Permalloy wires is a fail-safe element using a thin film parametron (T.F.P.). "Parametron" has been known as the failsafe element in automatic control fields. The T.F.P. is more suitable to the fail-safe element than a ferrite one with regard to speed, stability, and size. Thin Permalloy wires used are 81 Ni-Fe alloy with a thickness of 1 μm electrodeposited onto copper wires with a diameter of 0.47 mm. The uniaxial field-induced anisotropy was in the peripheral direction, and the anisotropy field was about 200 At/m. Output voltages of the T.F.P. are more stabilized than those of a ferrite parametron. This is one of the reasons why the T.F.P. is recommended as a fail-safe element. A test set with a twin binary counter of seventeen digits using about 300 T.F.P. fail-safe elements has been operated satisfactorily with an exciting current of 0.2 A rms and 50 kHz clock.