- #1
donpacino
Gold Member
- 1,439
- 285
I was just sent an email with the following text.
""
Here is a puzzle I just encountered.
Take any NPN transistor and ground the base. Now apply +12 volts to the emitter through a series resistor of 1k. Yes, it is a Zener diode of about 6 volts so about 6 ma of current flows.What is the voltage between the collector and ground? I couldn't guess. Well I could guess it was zero volts, but then, that would not have been a puzzle. So I gave up.Answer: about -0.4 volts ! (Yes negative.) Why?
""I am at a loss for understanding where they are getting this supposed -0.4V. Any takers?
edit: it is important to note my interpretation of the problem is the the collector is left open
""
Here is a puzzle I just encountered.
Take any NPN transistor and ground the base. Now apply +12 volts to the emitter through a series resistor of 1k. Yes, it is a Zener diode of about 6 volts so about 6 ma of current flows.What is the voltage between the collector and ground? I couldn't guess. Well I could guess it was zero volts, but then, that would not have been a puzzle. So I gave up.Answer: about -0.4 volts ! (Yes negative.) Why?
""I am at a loss for understanding where they are getting this supposed -0.4V. Any takers?
edit: it is important to note my interpretation of the problem is the the collector is left open