Design a circuit, using a darlington transistor, to monitor the voltage Vin which appears on an input line, and turn on an LED if Vin exceeds 4.8V. The circuit should run from +10V.
The current drawn from the line whose voltage is being monitored should not exceed 100uA.
Indicate component values.
(The correct answer is attached).
I am not sure about a couple of things:
*Shouldnt the 300k resistor be connected to the +10V positive rail (parallel to the LED), so that it is in line with the 100k (by voltage division)?
*Where does the input voltage (Vin) come from?
*Howcome the darlington transistor is connected as an earthed emitter, as opposed to emitter-follower?
The current drawn from the line whose voltage is being monitored should not exceed 100uA.
Indicate component values.
(The correct answer is attached).
I am not sure about a couple of things:
*Shouldnt the 300k resistor be connected to the +10V positive rail (parallel to the LED), so that it is in line with the 100k (by voltage division)?
*Where does the input voltage (Vin) come from?
*Howcome the darlington transistor is connected as an earthed emitter, as opposed to emitter-follower?
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