If adding a stay-alive capacitor, ensure its' voltage rating is at least as high as the DCC track voltage. Normally this is around 16V.

If possible, it is recommended that you use a capacitor between 25-35V. Any size will help, even as small as 100uF, but the bigger the better, up to 2200uF. Electrolytic and Tantalum capacitors may be fitted directly to the decoder as described in the decoder manual.

Gold Caps require additional circuitry.