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MARKET CENTRE Advertise your product or services here in Silicon Chip KIT ASSEMBLY & REPAIR FOR SALE DAVE THOMPSON (the Serviceman from Silicon Chip) is available to help you with kit assembly, project troubleshooting, general electronics and custom design work. No job too small. Based in Christchurch, New Zealand, but service available Australia/NZ wide. Email dave<at>davethompson.co.nz LEDsales KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand; * Small production runs. Phone Keith: 0409 662 794 keith.rippon<at>gmail.com LEDS, BRAND NAME AND GENERIC LEDs, filament LEDs, LED drivers, heatsinks, power supplies, kits and modules, components, breadboards, hardware, magnets. Please visit www.ledsales.com.au PMD WAY offers (almost) everything for the electronics enthusiast – with full warranty, technical support and free delivery worldwide. Visit pmdway.com to get started. Do I just run a wire through the bead on the PCB? (B. L., Melbourne, Vic) ● Yes, you just run a piece of wire through the middle; see Fig.13 in part two of the article. It can be a component lead off-cut, a length of tinned copper wire, a piece of solid-core insulated wire – anything that fits should work. The type of ferrite bead is not particularly critical. There’s space to use a fairly long one (up to maybe 12mm). Altronics L4710A should work; L4810A might also fit. Jaycar LF1250 should also work, but in that case, we’d be tempted to thread the wire through two beads since they are fairly short. Still, one would likely be sufficient in this application. ● We mentioned using JLCPCB for 3D printing in the Pico Gamer project article (April 2024; siliconchip.au/ Article/16207). Some public libraries also offer 3D printing services. 3D printing service recommendations Adjusting 2.5GHz Freq. Counter to 10MHz I was impressed with the excellent finish you achieved on the case for the Shirt Pocket Oscillator kit I purchased recently (September 2020; siliconchip. au/Article/14563). Can I obtain the necessary printed items for the ‘plastic tub’ version of the 3D Printer Filament Dryer project from you? If not, can you recommend a 3D printing service? (J. A., Townsville, Qld) I have a question about the trimming of VC1 on the 2.5GHz Frequency Counter (December 2012 & January 2013; siliconchip.au/Series/21). I am feeding a 1PPS signal in on channel A, set in period mode for one second and have a reading of 1000003μs, which is close but not on the money. When I try to trim to the correct reading of 1000000μs, I can only increase siliconchip.com.au 1kHz sinewave generator circuit I need a 1kHz sinewave generator. Have you published one? (R. M., Melville, WA) ● The Roadies’ Test Oscillator project (June 2020 issue; siliconchip. au/Article/14466) can be set up as a 1kHz oscillator. Just replace the 6.8kW resistors with 15kW values for a 1kHz output. Australia's electronics magazine PCB PRODUCTION PCB MANUFACTURE: single to multilayer. Bare board tested. One-offs to any quantity. 48 hour service. Artwork design. Excellent prices. Check out our specials: www.ldelectronics.com.au Advertising in Market Centre Classified Ad Rates: $32.00 for up to 20 words (punctuation not charged) plus $1.20 for each additional word. Display ads in Market Centre start at $82.50 per column centimetre per insertion. All prices include GST. Closing date: 5 weeks prior to month of sale. To book, email the text to silicon<at> siliconchip.com.au and include your name, address & credit card details, or phone (02) 9939 3295. it to 1000010, so 1000003 is the lowest it goes to. Is this normal? I have read that replacing the 39pF ceramic capacitor with a 47pF type will help in trimming, but I think it’s odd that I only have 7μs adjustment in the first place. Do you have any ideas what’s going on here? (E. B., Meadow Springs, WA) ● A trimmer capacitor in a crystal oscillator circuit will always have a fairly limited adjustment range. We would try changing the value of the fixed 18pF capacitor in parallel with the trimcap; it likely needs to be a lower value, like 12pF, to achieve calibration. Different crystals will have a different adjustment range. It’s possibly yours is particularly narrow, in which case swapping it for a different type with more ‘pull’ might help. Unfortunately, there is often no pull figure given in the crystal data sheet. Replacement relay for Soft Starter In the Soft Starter for Power Tools (July 2012 issue; siliconchip.au/Article/ 601), you used a relay from element14 that is no longer available. It was rated at 16A with a 24V coil. Can you December 2024  111