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    HP-456A Current probe – repair

    This HP-456A current probe is a real beauty. Released as a new product by the Hewlett-Packard Company in 1960, the 456A was HP’s first solid-state, stand-alone, clip-on current probe. Its elegantly designed amplifier uses two— then “state-of-the art”—PNP germanium transistors. The Original Probe In 1960, The Hewlett-Packard Journal (July-August, Vol. 11) proudly announced: “This new […]