RCL-meter is a low cost and minimal hardware solution for measuring:
– capacitances (5pF to 5uF)
– inductances (5uH to 50mH)
– resistances (5 Ohm to 50 MOhm)
using the PC soundcard.
The required external hardware is just 2 resistors and 2 capacitors.
Version 1.10 includes an improved phase shift measurement, making the software less critical toward the quality of the soundcard.
How it works
The working principle is simple: an AC voltage, with a known frequency, is applied over a known resistor (R) in series with an unknown impedance (X). Based on the voltage ratio (Ux/Ur), the phase shift between Ux and Ur the unknown impedance (X) can be determined.
However, implementing this principle using a soundcard is not so easy. At high impedances (X) Ur is close to 0 while at low impedances Ux is close to 0. In both case it is difficult to get a sufficient accuracy. Mainly because of the inaccurate phase measurement.
In addition the soundcard inputs have a rather low input resistance and a significant input capacitance, appearing in parallel to X.
In fact a soundcard is not really suited to build a RCL-meter, in particular due to the low input impedance and relatively large input capacitance. In addition there is a lot of variation between soundcards in regard with the input impedance, input capacitance, line-in sensitivity and speaker out level.
But it is probably the nature of a radio amateur to try to use things for purposes they are not designed for …
These problems were solved by taking the Fourier Transforms of Ur and Ux and use these to calculate the voltage ratio and phase shift. After using some tricks and a lot of calculations it seems possible to build a relative accurate (and very cheap) RCL-meter.
– As a lot of math is involved (3 FFT’s per measurement) at least a Pentium 200MHz with 8MB RAM (16MB or more preferred) is needed.
– Of course a soundcard that can handle 16 bit ADC / 44kHz sample rate. With older / cheaper soundcards the measurement accuracy can be limited, due to a strong internal coupling between speaker out and line in (see help file for details). In addition the soundcard MUST have a line-in input, as 2 signals must be measured at the same time the microphone input (as it is mono) cannot be used.
– At least Win98.
Officially LG doesn’t support transferring channel lists via USB on its consumer models because this is supposedly reserved for their premium “Hotel” models. But despite official denial there are hidden menus in all consumer models which give you access to the required import/export functions.
Choose any TV channel (it might not work if other input is selected)
Press and hold MENU/SETTINGS button on the remote control until TV’s menu appears, disappears and channel info appears.
Quickly release MENU/SETTINGS button, enter 1105 and press OK.
In the installation menu, you can change the following parameters:
LG Hotel mode setup (setting restrictions for hotels)
USB Cloning or TV Link-Loader for other model (load/save configuration (TLL file) from/to USB drive)
Password Change (reset forgotten parental PIN)
Models with number MA53xxx write 2 files on the stick. Only the file named xxMA53D-PZPxxxx.TTL is relevant, the GlobalClone.TLL should be ignored. ChanSort provides partial support to edit the xxMA53D-PZPxxxx.TTL files.
Asa cum spunea si titlul: Donez invitatii pe CzTeam (in limita stocului). Pentru a primi o invitatie am nevoie de adresa de email postata in comentariu (nu o sa fie publica).
De aceasta data regula nu este “primul venit, primul servit” ci “primul raspuns corect este si primul servit”. Ce raspuns corect? Raspunsul la intrebarea: Ce este raţia (ratio)? (nu ma refer la rația de mancare)