| 摘要 |
<p>PURPOSE:To set hysteresis width by a constant current value by a Schmitt circuit using a differential amplifier and constantcurrent supply. CONSTITUTION:Once an input voltage is applied, transistor 22 conducts and transistors 26-28 also conduct, so that transistor 26 will absorb constant current source I2. As a result, currents of diodes 36 and 37 decrease and the base voltage of transistor 26 falls through posivive feedback. Further, since transistor 29 is OFF and current I3 is supplied to transistor 25, currents flowing to diodes 36 and 37 decrease. Transistor 23 is biased by currents flowing through diode 36 and 37 and those current are varied to vary prositive and negative threshold voltages VT<+> and VT<-> independently.</p> |
