i have a SPDT toggle switch and trying to power two lights when switch is up and only power one light when switch is down, both lights off when switch is in the middle (neutral), how can i achieve this? i am using simple led strip lights, dc powered.
Figure 1. If you are switching DC a diode will allow the UP switch to switch on both lights and prevent backfeed when DOWN is on. D1 and D2 represent the lamps with current control (resistors or CC PSU) not shown.
One problem with this is a 0.7 V drop across D3. The D1 lights may dim slightly when switching from down to up. This may not be a problem since you pass through the OFF position.
Figure 2. For AC the diode won't work. A relay solves the problem.
If your lights are powered from DC, then a simple diode connection will work. Connect both lights through separate diodes to one side of the switch, connect one light through a diode to the other side of the switch; switch common is ground. Choose diodes to suit current loads.