19 kHz precision calibrator - a simple test-instrument calibration aid

19 kHz precision calibrator elektor march 1985 a simple test- instrument calibration aid 19 kHz precision calibrator Test instruments are essential for any serious laboratory, be it "professional" or a hobbyist"s workshop. Bad test equipment, on the other hand, can be worse than no equipment at all as it gives wrong impressions that are likely to be taken as "truths". Accuracy is always a point of doubt with home-made test instruments and for this reason we were very careful to give a detailed test procedure for our recently-published frequency counter. In hindsight, however, it occurred to us that one point could be considered as an example of "Catch 22": a good frequency counter was needed to calibrate the crystal oscillator, To remove this difficulty we came up with a simple, but accurate, circuit. 3-52 A test instrument must be reliable and accurate and, in general, the more you are prepared to pay the more of these two qualities you can expect. Home-made equipment is somewhat...