Power Resistors Series Vishay Power Resistors Series includes 4 types ranging from 5W to 50W. Vishay Power Resistors Series components are designed to be mounted onto a heatsink and can bear high short-time overloads. Three types of terminations are available. The resistors are non-inductive and are particularly suitable for high-frequency operation and cut-out circuits. -RCH Series: 5 W to 50 W, with high power rating and high overload capabilities. -D2TO20 Series: 20 W at 25ºC surface mounted resistor. -RTO Series: 20 W at 25ºC with high power dissipation to size ratio, wide resistance range, and negligible inductance. -LTO Series: 30 W at 25ºC and is an extension of the RTO Series with direct mounting ceramic on a heatsink.