Tuesday the 12th of August 2014 saw the monthly get-together for the South Essex Amateur Radio Society (SEARS). On the agenda for this well-attended club night in Thundersley was the subject of circuit design.
Circuit Design & Veroboard Layout
The evening’s talk was presented by Dave G4AGJY, who introduced us to the topic and walked through an example of designing a CW oscillator.
Dave started out by discussion how designs often start – on the back of a fag packet, and then migrating it to an on-screen layout. Dave’s package of choice for circuit layout is the free package TinyCAD.
Switching from presentation to a live demo, Dave ran through the basics of component selection and layout. One of the advantages of this approach is that it’s possible to run a simulator on a design to test it. With the values of the components added to the schematic, the simulator can show you what results can be expected from the circuit on screen without the need to construct anything.
Once tested virtually, Dave’s next approach is to use TinyCAD to produce a Netlist – an exportable list of components. This can then be imported into the veroboard design software package VeeCAD. Again, switching to a demo of the software allowed Dave to show the audience how to add components, break the veroboard tracks, and check the layout for error such as shorts or unconnected components.
A nice touch that wasn’t apparent from the start of Dave’s talk is that he’d brought along all of the hardware to demonstrate – bits of uncut veroboard, the track-breaker tool, printed circuit boards, and a fully constructed CW oscillator made from the TinyCAD design and assembled on veroboard using the VeeCAD tool.
To end the talk, Dave produced a finished, boxed, working CW oscillator for everyone to try.
A great example of how to do a good demonstration – talking through a project, start-to-finish, handing out kit for those not familiar with the various items being discussed, and ending with a demonstration of a working finished product – An excellent well-planned talk giving a solid introduction to the use of free software for circuit design and board layout.
Next club night for SEARS: Tuesday 9th September – a talk by Justin G0KSC from Canvey-based Innovantennas.
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