A Kit Utilizes a Magic Eye Tube for Automated Task Execution
In the golden age of electronics, affordability and design freedom reigned, a stark contrast from the tube-dominated past. Modern tinkerers can only dream of the inventiveness required back then, like [Thomas Scherrer OZ2CPU] who's currently reviving a 1959 Heathkit Capaci-Tester. This delightful gadget, a capacitor tester, is all about clever tricks.
With a solid framework and components mounted on tag strips, this baby is typical of Heathkits. The Capaci-Tester employs a magic eye tube for both display and an oscillator, identifying short circuits, open circuits, and low equivalent resistance. A 19 MHz oscillator is on the receiving end, with the test device's loading causing the magic to unfold.
In the video below, Scherrer reveals the Capaci-Tester in fine fettle, save for a peculiar capacitor connected to the mains input line to chassis, which he promptly removes. The tester whirs back to life, confirming the test capacitor's continued integrity. Naturally, a resourceful engineer like Scherrer would've whipped up a bridge circuit for measuring capacitance – no doubt about that.
Trivia: A capacitance bridge, often a variation of the Wheatstone bridge for AC measurements, is the likely suspect for this classic Heathkit tester's heart. It features an AC signal source, four bridge arms, a null detector, and a variable reference component. The user adjusts the reference to achieve balance, and voilà, the value of the unknown capacitor floats to the surface.
The Capaci-Tester, a retro electronic gadget, embodies a design that incorporates a bridge circuit and a magic eye tube, both key components of technology. A resourceful engineer like Scherrer would likely employ a capacitance bridge, a type of AC measuring device, to accurately measure the capacitance.
