Frustrations of sourcing parts

January 16, 2020

Novice Designer

When I started out with electronics, I had some old copies of Practical Electronics magazine from a friend of my parents.  These were good in that they provided a variety of different projects and circuit ideas. However, because they were old, I found that the components they mentioned were not easy to source.  At the time I was not aware that many components have an equivalent, either in a different case style or with slightly different characteristics. At school in our design class, we used a general-purpose NPN transistor the BC108 in a small metal can. This was good for the simple switching circuits we made at school. When I came to buy components for my own project, I realised that the BC548 was equivalent but slightly cheaper. So I bought a bag of those and used them in many projects in the future.

Similarly with OpAmps the 741 was the go to device for amplifiers and comparator circuits. But since then there have been many new integrated circuits designed so it is rarely the best choice. For example when I was building a piezo “knock” sensor circuit for the Enchanted Cottage, I picked a LM393 as it could work with the lower supply voltage I was using, it also had a full swing output which was important for the logic circuit I was connecting to. Having the right electrical characteristics is one main consideration when sourcing parts. Running components out of their intended range can introduce reliability issues.

Repairs

When you are designing and adapting other circuits you may have a wider choice in the alternatives you select.  However, when repairing there are other considerations to take into account. For example, the physical size and shape of the component might be important. Sometimes for cosmetic reasons but often for the simple case of needing to solder them to existing holes. Sometimes pins or tracks need to be cut and rerouted using wires. If swapping a smaller component then an adapter PCB can work for this situation.

Pro-Maker

If you are thinking of becoming a pro maker then scaling up component purchases needs to be considered.  You might be able to gain a price advantage by accepting longer lead times but if you have sudden surges is demand then an alternative supplier could be useful. When designing for the long term, you also want to consider component obsolescence.  Can you still get the same parts in 5 or 10 years time? There are initiatives such as the Common Parts Library for Production that can help buy restricting your components to a list that is used by a wide variety of people. This can also help when manufacturing as you won’t need to send components to a contract manufacturer. Another recommendation is to use parts used by industries with long aftercare times such as automotive or even aerospace. Using parts common with these could lead to savings and a good long term supply.  Look for “Long Term Support” listed against the components and see if your supplier recommends alternative parts.

Winsource Review

Nico from Winsource suggested I check out their website for common-used, end of life and obsolete components. I had a look and the site is easy to navigate on both desktop and web. You can drill in by category or go straight for the search. I picked a slotted opto-sensor as an example, as for a previous project that had shown to be hard to track down, particularly in Australia. The pages have clear details for the part including datasheets and in some cases, models to add to your CAD software. I was pleased to see the site had motors and servos as well as the expected electronics components. As a hobbyist, one downside was the minimum quantities. These all seemed to be geared up to make an order of around $50.  So for my slotted Opto-Switch example, you’d need to get 60. This would, however, be ideal for prototyping or small production runs.

In comparison to UK suppliers there did seem to be price advantages. But remember that WinSource are based in Hong Kong so you need to factor in shipping costs and times. For this, there are multiple options depending on your time and price sensitivity.

In summary, a good place to get small batches of common components, (End of Life) EOL and obsolete parts.

About WIN SOURCE

WIN SOURCE is an industry-leading AS9120 ISO 9001:2008 ISO14001 certified electronic components distributor, specializing in offering a wide range of obsolete and common-used electronic parts, with cost-effective alternative solutions of electronic parts. An online electronic store, offers online line card, inventory, and purchasing.

For more information contact:

WIN SOURCE ELECTRONICS

Phone: 0086-755-83957316

E-mail: [email protected]

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By Andy from Workshopshed Add Comment

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