. Electronic apparatus for biological research. Electronic apparatus and appliances; Biology -- Research. SINGLE SQUARE WAVE GENERATORS not seem to the author to be electrobiologically interesting and so has not been described, but the triggered version is important and will be dealt with now. In the transitron a pentode valve is used, but not in the classical pentode manner, where the screen-cathode and suppressor-cathode potential dif- ferences are constant. Instead, the screen is used as a kind of subsidiary anode and the suppressor as a second control grid. Not many pentodes make good tran
. Electronic apparatus for biological research. Electronic apparatus and appliances; Biology -- Research. SINGLE SQUARE WAVE GENERATORS not seem to the author to be electrobiologically interesting and so has not been described, but the triggered version is important and will be dealt with now. In the transitron a pentode valve is used, but not in the classical pentode manner, where the screen-cathode and suppressor-cathode potential dif- ferences are constant. Instead, the screen is used as a kind of subsidiary anode and the suppressor as a second control grid. Not many pentodes make good transitrons because the controlUng effect of the suppressor of most pentodes is insufficient. At the time of writing the Mullard EF 50 and the Mazda 6F 33 are conspicuously good for transitron action. Figure shows the circuit. When it is quiescent, the suppressor poten- tial is such as to encourage a substantial anode current and a much smaller HT+. Figure screen current, as in normal pentode usage. If now a negative trigger pulse be apphed to the suppressor the anode current is reduced and electrons flow instead to the screen, increasing the screen current and reducing the screen potential. This reduction is transferred via C to the suppressor, producing a further fall in anode current and increase in screen current. Cumulative action then occurs as a result of which all the cathode current goes to the screen and the anode current is cut off. This state of affairs persists until, as a result of re-adjustment of the charge on C, the suppressor potential returns exponentially to a point at which anode current once more begins to flow. The screen current then falls, the screen potential rises and a reverse cumulative action occurs. The waveforms are similar to Figure , except that screen potential should replace V-^ anode potential, and suppressor potential the V^ grid potential. Uses for single square waves—^The pulses produced by the flip-flop and transitron may be
Size: 1943px × 1286px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
