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| Function of this diode....image included |
| (1/1) |
| xwarp:
I'm drawing a blank on the function of the diode, but I'm going to guess it's suppose to help turn the transistor off? :-// :palm: So the open end of R3 has a either a low input, or, +5 via a pullup. VDD is +24 vdc When the circuit it "on", it provides +24 vdc from VDD through the collector to another circuit. Help me remember what I've forgotten, or, what I never knew.....lol Thanks! |
| GromBeestje:
What kind of load is this circuit supposed to drive? If it is some inductive load, it might be a flyback diode. If you remove the power from an inductive load it will generate a voltage in the opposite direction. A flyback diode will allow that surge to be dissipated. Otherwise it will blow up your transistor. |
| Nusa:
Generally it's there to protect the transistor from feedback. In some transistors, it's integrated in the transistor package. |
| graybeard:
If the base-collector junction becomes forward biased by a difference in the collector voltage and vid the diode will turn on preferentially since it has no external series resistance and prevent and significant current flow in the base-collector junction. However since the entire circuit is not show it may be there for other reasons. |
| xwarp:
I unfortunately do not have the schematic for the circuit this output supplies. The input of the circuit that the VDD output goes to begins with several resistors. I believe to be essentially voltage dividers, so essentially a resistive load. |
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