Hi, firstly apologies for what might seem like a 'basic' question, but I've been trying to work this out for a while. I have a sealed lead acid (SLA) battery - 6V 4AH. I would like to use this battery to power a 4V coil (for a display) - that is capable of (potentially) drawing the full 4A from the battery. I would like to know what value potentiometer (or more likely rheostat) I need to use in the circuit. The output of the pot should be betweeen around 3V and 4V (2V - 4V would be ideal), at the full 4A. The coil is for display, so I'd like to use a 'manual' device such as a rheostat / variable resistor, rather than a step-down transformer or voltage regulator circuit. Thank you in advance for any hints / suggestions. Russell.