HVP High-Voltage Planar Resistors Welwyn / TT Electronics HVP High-Voltage Planar Resistors are high-reliability resistors ideal for medical applications. The HVP series includes powder-coated resistors that provide high stability in humid conditions. Welwyn HVP resistors offer voltage ratings up to 20kV in a non-inductive, compact planar format. The series also offers resistance values up to 10G.