Technical Articles

Electrical feedthroughs by type and application

Allectra is an established Electrical feedthrough specialist with over 20 years experience manufacturing and supplying a wide range of feedthroughs for customers all over the world.

The Sub-miniature D Type feedthrough is based on the electronics industry standard MIL-C-24308. These are available as  9, 15, 25, 37 and 50 way feedthroughs and also multiple and custom feedthrough flanges. Accessories include UHV, PEEK, ceramic and air side sockets.

Allectra supply weldable versions suitable for TIG welding.

Special versions, e.g. 9 pins on a 25KF flange or 25 pins on a 50KF flange require vacuum side connectors without the mounting screws while standard air side connectors will fit.

Multiple feedthrough flanges are available as standard, CF and ISO-K, or custom. We have in-house manufacturing which means fast delivery and we will either produce drawings for customer approval or work with a customer’s own drawings. This is our standard procedure for special fabrications.

Titanium feedthroughs welded to Titanium flanges are available on special order.

Combination feedthroughs offer a mixture of Power pins, Coaxial pins and Standard pins in one shell. The Power pins are ideal for heater applications.

High Density Sub-D feedthroughs offer more pins on the same shell size:  instead of 15 pins we can fit 26 pins or in the case of 50 pins we can fit 78 pins. This is achieved through reduced pin diameter and a closer pitch. For the vacuum side, PEEK connectors are available.

Allectra offer 12 and 19 pin Circular Miniature feedthroughs and 6 pin High Current versions. The industry standard air side connectors are shielded and EMC compliant. All air side connectors are metric threads. Used in combination with vacuum side housing,  it is possible to achieve a fully shielded connection from air to vacuum.

Dual In-line feedthroughs are used for a direct connection to Printed Circuit Boards on either air or vacuum side. Typically, the electronic board is connected to the air side to give the shortest signal path. Up to 3 feedthroughs will fit onto a 63CF flange providing 120 signals.

Standard BNC feedthroughs are an economic, general purpose coaxial solution, where defined impedance and high voltage are not required. Up to 4 feedthroughs will fit on a single 40CF or 40KF flange, either single or double-sided and in-vacuum cables are available for both types.

The 50 Ohm BNC feedthroughs are suitable for high frequencies. The double-sided version can be used up to 4GHz. Air-side sockets are included and in-vacuum cables are available for both versions.

Allectra offer a SMA 50 Ohm miniature Co-axial feedthrough for applications up to 18GHz . With this miniature size, up to 4 feedthroughs will fit onto a 40CF or 40KF flange, with DC (direct current) to 6.5GHz or 18GHz. This feedthrough is available double-sided with both internal and external 50 Ohm plugs.

If 18GHz is not enough, Allectra offers a microwave feedthrough, SMA-K type (2.92mm) for up to 40GHz.

Allectra also now offers a double-sided SMA feedthrough for UHV with an extended frequency range up to 27GHz. This is in addition to the 18GHz SMA Feedthrough. These “Super-SMA” versions are a cost effective alternative to the SMA-K or 2.92mm types, if frequencies above 27GHz are not required. Housing is Stainless Steel with gold plated centre contact. The smallest mounting flange is 16CF. Up to 4 of these feedthroughs can be fitted to a DN40CF flange.

MHV (Miniature High Voltage) and MHV 50 Ohm feedthroughs are more suitable for higher voltage applications than BNC, with increased voltage rating. Both versions are available single-sided, double-sided and floating shield.

The Allectra SMB feedthrough creates an alternative to the well established SMA types. With this newer feedthrough, small dimensions are combined with a frequency range up to 1GHz and in-vacuum connectors and cables are available at more cost-effective prices.

Safe High Voltage (SHV) feedthroughs are Coaxial feedthroughs designed to provide a secure high voltage connection on the air side. On the vacuum side they come in two versions: recessed ceramic and exposed ceramic. The feedthroughs are available as standard (5KV) or a special version is available  (6KV) with 50 Ohm impedance.

SHV10 are Safe High Voltage feedthroughs rated for 10KV and SHV20 rated for up to 20KV. Air-side connectors are included for both types.

Allectra also offers 50 Ohm Type N feedthroughs for high frequency signals up to 200MHz.  7/16 feedthroughs are offered as High Vacuum versions only and are suitable for applications where high power and high frequency are required.

Between Series feedthroughs are offered with Microdot on the vacuum side and BNC on the air side.  Cables are also available with combinations of Microdot to Microdot, BNC or SMA connectors.

Allectra offer a range of Power feedthroughs. Low voltage types are 500V and 1KV.

500V feedthroughs are very small and so ideal when space is limited. 1KV feedthroughs are for general purpose instrumentation use.

These feedthroughs rated at up to 5KV and up to 20A come as single pin weldables with up to 4 pins on a 16CF or 16KF flange. Custom arrangements available on a choice of flange on request. There are also 5KV and 10KV feedthroughs up to 30A. These have up to 12 pins on a 40CF or 40KF flange.

High Current feedthroughs up to 1000A are suitable for heaters, furnaces and Electron Beam Evaporation Sources. A range of types is offered as weld adaptors or on KF or CF flanges. For very high current, a 1000A water cooled feedthrough is available.

Allectra also offer Multi-way feedthroughs with MS Circular Sockets, with 10, 23 or 40A per pin. The sockets comply with MIL-C-5015. High Voltage 12KV Multi-way feedthroughs are also available with 7.5A per pin.

Power Glove feedthroughs are a design of High Voltage 5KV, 10KV, 20KV to 40KV feedthroughs and are supplied with sockets and air side cables  2.4m in length. There are options for 1, 2 or 4 pins on a 40CF flange or the feedthrough can be supplied on CF, KF, ISO or custom flange designs.

High Voltage feedthroughs are offered in ratings up to 60KV. They are not built for high currents as high voltage and high current are typically not used together.

However, Tube feedthroughs are suitable for liquid cooling applications where higher currents and high voltage are used together.

Baseplate feedthroughs are designed to fit through a 1″ (25.4mm) hole and sealed by compressing an O-Ring between 2 nuts. Applications for these feedthroughs include High Vacuum Coaters. Many of Allectra’s feedthroughs can be supplied as Baseplate types.

Baseplate (Bulkhead) Sub-D feedthroughs are available for applications down to 10-7 mbar. These feedthroughs can be used with aluminium chambers as they are bolted. Rectangular base plate 9/15/25/37/50 pin feedthroughs are  available.
Other feedthroughs are mountable to the same base plate (Coaxial for example). Base plate dimensions are the same for all feedthroughs making them easily interchangeable.

Baseplate (Bulkhead) Sub-D feedhrough shown right

Thermocouple feedthroughs have pins made from the corresponding thermocouple pair materials. On the vacuum side, the pins terminate with a screw connector (included). The (+) pole is 25mm shorter than the (-) pole. Miniature Thermocouple connectors are included for the air side.

In addition to the popular K, N and C Thermocouples, Allectra offers the special purpose R, S and T types. Types R and S share the same feedthrough pin material (R- extension grade). Type T is particularly suitable for cryogenic applications.

Additionally, types E and J are available to order.

Combination Power/Thermocouple feedthroughs are intended for heaters where both power leads and temperature measurement are required. These feedthroughs are offered with either Nickel or Copper conductors and either K or C type Thermocouple connectors and are available up to 150A.