High Power Semiconductors

Specialist Electronic Semiconductor Suppliers

Welcome to Harmsworth, Townley & Co. Ltd:  Specialist providers of High Power Semiconductors to the power rectification industry for 70 years.

Whether you need spares, repairs, maintenance, breakdown response, refurbishment, OEM – or are just in need of a part quickly– we can help you. We provide a fast-response service in case of breakdown, send goods worldwide and even offer a same-day delivery for emergency breakdowns.

Our bespoke service is very popular – creating components to fit your requirements. We often provide modern equivalents of obsolete/no longer manufactured devices – whether it’s for on those off-shore oil rigs or keeping underground trains running!




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About Us

We are recognised distributors with engineering supply and dedication which is second-to-none. founder Mr WG Townley was a refugee from Nazi Germany who went onto serve in the REME (Royal Electrical and Mechanical Engineers) in North Africa and Europe during WWII. He launched the business in 1946, whilst still continuing his electronics education under the guidance of professors at The University of Manchester. The business made significant progress in semi-conductor supply – going on to become the first and at the time only worldwide Westcode distributor– and over the decades providing hundreds of jobs.

To this day we are proud to have one of the largest stocks of Westcode Power Semiconductors and Bussman and GEC semiconductor fuses in the UK, and are also honoured to be the UK distributor of Hind Rectifiers.

Providing those hard-to-find components is something we specialise in; with a personal service throughout. Personally picking, packaging and dispatching your order matters to us – in the fastest possible time for your convenience. We’re even adding a small gift with each order – an eco-friendly bit of fun, thanks to our ‘Eco-Life Gizmos’ range – from June 2016 onwards.

Our frequently updated stock includes a variety of diodes, thyristors and fuses for range of industrial uses.  Clamps, leads, sleeves, heatsinks and heat-sink compounds are also available. Some of our worldwide customers also ask us to source other items for them, as they trust our personal approach and reliability.

Other areas of provision include solid state relays, IGBTs and varistors. A number of rectifier services are also available; which include rectifier assembly, bridges and hardware components: with Westcode Rectifier stacks built to order.

We also have an extensive stock of IR-Vishay semiconductors and many obsolete devices too. We can source from manufacturers including Semikron, Infineon, Eupec, Mitsubishi, Lawson and Ferraz.  Brand quality matters to us.

We stock a huge standard range of components as well as obsolete items, enabling fast turnaround, and all products are frequently updated. With an extensive client base, many of our customers have been returning to us for years – from areas including power generation, telecommunications, transportation and aviation.  That is not all; for we also have connections in farms, funfairs, sugar mills, launderettes, garden centres, university research departments, schools and colleges – there is no limit!

Our Range is extensive and regularly updated, always keeping ‘engineering support’ in mind, with a wide range of semiconductors in stock. This includes but is not limited to diodes (with a range of specifications available), thyristors, fuses, varistors, leads, solid state relays, IGBTs, power modules and rectifier bridges.

Obviously stocks change every day but a snapshot shows 2500 lines and almost half a million items in stock. Browse away or give our team a call.

On the rare occasions where we don’t have what you need we will do everything in our power to source alternatives for you, even when that means having them made specially.

Our staff although all specialists in their own areas are very adaptable and during their service have learned about all areas of the business – so we’ll always be there for you even when one of us is on holiday or away.

You can continue to rely on our long established name and fantastic track record of supporting engineering industries since 1946. Our internal quality systems go above and beyond the ISO requirements – we think the quality of our goods and service matters for every single quote, order and item and is not just down to a tick in a box or a report on a shelf.


IXYS UK Westcode introduces a new 3.2kV distributed gate thyristor

IXYS UK Westcode Ltd. announces a new higher voltage class pressure contact distributed gate thyristor. This new fast thyristor with turn‐off time of as little as 65μs and current range of 1055A, is symmetrical blocking with Vdrm/Vrrm equal to 3200V and therefore suitable for both voltage and current fed applications.

IXYS UK Westcode re-launch 7kA welding diode

IXYS UK Westcode Ltd. Announces the re-launch of a 7kA welding diode in industry standard 8.5mm low profile ceramic package. The 200V to 400V device has been reengineered to meet the demanding needs of the application, while retaining an acceptable balance against the...