How can I switch a high current with a low-rated switch?
To return to your transistor solution (as others have opted for a different mechanical switch), it might look like this. I included Wouter's hint for using a diode instead of the second transistor. Also I changed the bipolar transistor to a MOSFET. Reason for a MOSFET is because the base current of a bipolar transistor gets rather high with regular power transistors. Reason for P-channel high side switching is that this way the load can be attached to ground. If this is not a requirement, the circuit can be slightly changed to support an N-channel MOSFET.


D1 should be rated > 2A
T1 should be rated Id > 2A (P-MOSFET)








simulate this circuit &ndash; Schematic created using CircuitLab