On Sun, 4 Sep 2022 at 11:57, Hans Wagemans <on4cdu@...> wrote:
I don¡¯t have one, but this LCR meter from Hungary quite impressed me Note it is 4-terminal, and works on the principle of an autobalancing bridge, like at least some of the HP/Agilent/Keysight ones do. My Agilent 4284A (0.05% basic accuracy) works on that principle. On my HP 4284A one has to enter the length of the test leads (either 0 m, 1 m, 2 m or 4 m). There¡¯s no facility to enter the test lead length on that meter.? I don¡¯t know why HP consider the test lead length important, but they obviously do. On the 4284A, option 006, which adds support for 4 m test leads, was an extra cost option. It¡¯s a software only option, but the instrument needs recalibration - I assume to check the 4 m results meet the specification. My meter didn¡¯t originally have that option, so I asked Keysight the cost of upgrading. They said when I sent it for calibration they would add it free of charge. The maximum frequency of the 4284A is 1 MHz (wavelength of 300 m), so even 4 m test leads are very small compared to the wavelength.? Obviously 2 different imp¨¦dances would present the same impedance at the end of test leads, if those leads were of a different length. But I would have thought that as long as the 4 test leads were of the same length, the 4-wire Kelvin connection would have compensated fully for the length.? Dave? Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@... Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom |