| History & Topics |
| Can you estimate such a small inductor? |
 |
| Difficult, even if you have an access to the
laboratory equipments because of the connection errors. (Often, stray
inductances of the lead wires are greater than the "unknown".)
Digital Dip Meter solves the problem. Terminate (solder) the unknown coil with 100pF mica capacitor with shortest possible lead length, check resonant frequency with the Digital Dip Meter and calculate the unknown inductance by the following equation: L (micro H) = 25400 ÷ ( f × f × C ) where f is the resonant (dipped) frequency in MHz and C is the terminated capacitance in pico Farad. Resonant frequency of a coil above left with 100pF capacitor will be about 100MHz, where you can observe a clear dip on the indicator meter. Since the accuracy of frequency display is more than enough, the overall accuracy is equivalent to that of the capacitor. The measured inductance of the coil shown above at left is 0.026 micro H, meanwhile, the zem clip on the right has an inductance of 0.062 micro H. |
| History & Topics - INDEX |
| DELICA MITA MUSEN KENKYUSHO LTD |