I've been trying to create a simple transistor circuit with a 2N3904 that will toggle a geared DC motor on and off without drawing power from the arduino - I've followed the schematic seen in the 2nd image.
The circuit isn't behaving as I expect it to. For testing purposes, I've been feeding the 5V from the arduino into the base pin (before the resistor) to activate the 'switch' of the BJT. This only powers the motor when I have a low valued resistor at the base (~10ohms). When I use 1k resistor, the motor does not turn on. Also, I have used a digital pin set at high to attempt to power the base pin and toggle the motor on/off, but this does nothing, regardless of the value of the resistor.
Perhaps my circuit is incorrect? All I want the circuit to do is turn the motor on and off when I feed it a high signal from the arduino.
Notes: The red wire coming into the node at the top is from a 9V battery. The ground bus on the breadboard has both the arduino ground and battery ground connected to it.