Billy Mayo
Member
My Manager said that the input capacitance on TTL and CMOS gates need to be discharged, because they they aren't discharged using a pull down resistor , it will delay the output or create add a XXX nano seconds delay
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Not true. Usually the input of a logic gate is driven by another logic gate.My Manager said that the input capacitance on TTL and CMOS gates need to be discharged, because they they aren't discharged using a pull down resistor , it will delay the output or create add a XXX nano seconds delay
So is PF= 0.7 is it leading or lagging?
the OP said:PF= 0.7 is not sinusoidal?
the OP said:Only PF=1 is sinusoidal right?
Normally a transistor switch has no hysteresis. It simply switches on or switches off.
You can add hysteresis to a transistor switch if you want.
Hysteresis is simply some positive feedback
When you want a slowly changing input voltage to switch something on and off.When do you need to add hysteresis to a transistor switch? when the input on the base is what kind of signal?
The input voltage changes slowly then passes the threshold voltage. Then the output increases the input voltage with positive feedback to make the output switch very quickly.Why would a designer add hysteresis to a transistor switch? for what reason?
Why would positive feedback give you hysteresis?
a comparator is a good example of a circuit that needs hysteresis. Since its gain is 100,000 to a few million then it oscillates at a high frequency when an input gets close to its input threshold voltage. Adding hysteresis makes the output switch suddenly high or low.To me when a transistor switch has hysteresis it becomes a comparator switch?
the OP said:Why would a relay chatter with a switch with no hysteresis?
th OP said:Does adding hysteresis change the on and off levels? Off is at zero volts but hysteresis can make off and On have different voltage points
the OP said:To me when a transistor switch has hysteresis it becomes a comparator switch?
The transistor needs current flowing into the base to get it on, that is what R172 and R71 achieve.
the input to U6A and U6b turns Q1 on. The +15V rail turns Q2 on.