Maryland Ceramic & Steatite Co., Inc.  formed the Maryland Plastic Division in 1955, to supply plastic forms to the resistor industry for wire wound resistors. These resistor forms, commonly referred to as Bobbins, are either molded, made on a Swiss screw machine or plunge ground on centerless grinders.

What is a resistor (Bobbin)?

A resistor (bobbin) is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to: reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.



Maryland Plastic Products offer both molded and machined bobbins in a wide range of standard sizes. We have the ability to producing bobbins up to 1″ OD and 2″ L with little to no tooling. Custom sizes are also available.  For more information on bobbins contact our sales department.


Molded DAP Bobbins

Screw machine





With and without leads