Electronic apparatus for biological research electronicappara00dona Year: 1958 RESISTANCE AND CAPACITANCE IN SERIES At this point the reader may accuse me of doing precisely what I have warned against; namely, of converting voltage ratios into decibels with insufficient reference to the resistances across which the voltages appear. He may further ask, what is the point of considering the behaviour of net- works to which no useful load is attached ? The answer is that the filters in Figures and are frequently used to feed a valve, which constitutes a load, but a load whose resistanc
Electronic apparatus for biological research electronicappara00dona Year: 1958 RESISTANCE AND CAPACITANCE IN SERIES At this point the reader may accuse me of doing precisely what I have warned against; namely, of converting voltage ratios into decibels with insufficient reference to the resistances across which the voltages appear. He may further ask, what is the point of considering the behaviour of net- works to which no useful load is attached ? The answer is that the filters in Figures and are frequently used to feed a valve, which constitutes a load, but a load whose resistance is substantially infinite, and which therefore does not influence the operation of the filters. If the load resistance is infinite in all cases, we can convert voltage ratios into decibels without hesitation. As an exercise, the reader may care to consider what happens when the simple R-C high- and low-pass filters are fed from a real generator and work into a load which is not of infinite resistance. R-C filters comprising cascaded sections Suppose Fin is the sum of two alternating voltages of frequency co^ and Wg, and that we wish to filter out as much as possible of the contribution of the generator working at 0)3, the higher frequency. We use, of course, a low-pass filter {Figure ). If m^ and oj^, are close together, the dilTerence in the Frequency^ IS (O WWW Frequency (r,^ is a; 2 f Voui Figure __L Attenuation received with wide spacing
Size: 1676px × 1193px
Photo credit: © Bookend / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
