Hi, i'm working on a project at school and have a problem with using a sensor to trigger a transistor.
The circuit is shown below. Basically i want the relay to be on when the sensor gives an output of 5 volts, and off when it drops to 0.4 volts.
However, connected to the base of an NPN transistor, the BE voltage reads 0.43V?
Could someone suggest how to fix this problem or a different technique involving the 5volts output from sensor and a relay?
the 8.8kohm resistor is the resistance of the sensor so i assume it needs to be there :s
Thanks a lot, Nick
The circuit is shown below. Basically i want the relay to be on when the sensor gives an output of 5 volts, and off when it drops to 0.4 volts.
However, connected to the base of an NPN transistor, the BE voltage reads 0.43V?
Could someone suggest how to fix this problem or a different technique involving the 5volts output from sensor and a relay?
the 8.8kohm resistor is the resistance of the sensor so i assume it needs to be there :s
Thanks a lot, Nick
Attachments
Last edited: