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Instead of BJT, using a MOSFET will be effective since the transistor you used (2N3903) have maximum collector current of 200 mA whereas Motor specifications tellstell us that the load current is 300mA.

enter image description hereenter image description here

Also as Michael said, You are using a battery of 3V where aswhereas the motor needs 12-24 voltage as it's spec told. So you have to replace a battery with the new one of 12V or 24V capacity.

Also, in order to prevent transistors from frying of inductive loads, either it is MOSFET or BJT you need a Flyback diode, not a current limiting resistorsresistor. Because inductive loads will generate voltage spikes when you turn off the circuit and it will fry your transistor. So you need to provide a path for those voltage spikes after the circuit is switched off. That is why Flyback diode is used here.

Here is the recommended circuit for your requirement

enter image description hereenter image description here

EDIT: As Trevor mentioned in a comment, Rgate Resistor (R2) is added in a circuit.

Instead of BJT, using a MOSFET will be effective since the transistor you used (2N3903) have maximum collector current of 200 mA whereas Motor specifications tells us that the load current is 300mA.

enter image description here

Also as Michael said, You are using a battery of 3V where as the motor needs 12-24 voltage as it's spec told. So you have to replace a battery with the new one of 12V or 24V capacity.

Also, in order to prevent transistors from frying of inductive loads, either it is MOSFET or BJT you need a Flyback diode not a current limiting resistors. Because inductive loads will generate voltage spikes when you turn off the circuit and it will fry your transistor. So you need to provide a path for those voltage spikes after the circuit is switched off. That is why Flyback diode is used here.

Here is the recommended circuit for your requirement

enter image description here

Instead of BJT, using a MOSFET will be effective since the transistor you used (2N3903) have maximum collector current of 200 mA whereas Motor specifications tell us that the load current is 300mA.

enter image description here

Also as Michael said, You are using a battery of 3V whereas the motor needs 12-24 voltage as it's spec told. So you have to replace a battery with the new one of 12V or 24V capacity.

Also, in order to prevent transistors from frying of inductive loads, either it is MOSFET or BJT you need a Flyback diode, not a current limiting resistor. Because inductive loads will generate voltage spikes when you turn off the circuit and it will fry your transistor. So you need to provide a path for those voltage spikes after the circuit is switched off. That is why Flyback diode is used here.

Here is the recommended circuit for your requirement

enter image description here

EDIT: As Trevor mentioned in a comment, Rgate Resistor (R2) is added in a circuit.

1
source | link

Instead of BJT, using a MOSFET will be effective since the transistor you used (2N3903) have maximum collector current of 200 mA whereas Motor specifications tells us that the load current is 300mA.

enter image description here

Also as Michael said, You are using a battery of 3V where as the motor needs 12-24 voltage as it's spec told. So you have to replace a battery with the new one of 12V or 24V capacity.

Also, in order to prevent transistors from frying of inductive loads, either it is MOSFET or BJT you need a Flyback diode not a current limiting resistors. Because inductive loads will generate voltage spikes when you turn off the circuit and it will fry your transistor. So you need to provide a path for those voltage spikes after the circuit is switched off. That is why Flyback diode is used here.

Here is the recommended circuit for your requirement

enter image description here