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Coming up in Silicon Chip A switchmode replacement for 78xx series regulators The 78xx series has been around for yonks and is still very useful today. But when there is a high input-output voltage differential, or you need a lot of current, linear regulators generate a lot of heat and have poor efficiency. This small board is a drop-in replacement for a TO-220 package linear regulator. It's up to 96% efficient, needs no heatsinking and has various output voltages from 3.3V to 24V. Infrared Remote Assistant Remote controls are convenient and all, but sometimes you have a press a sequence of buttons on different remotes. For example, this may be the case to set up your home theatre system for a particular input. In many cases, other family members may not wish to learn the complicated sequences. The IR Remote Control Assistant can help, by recording and playing back simple or complex sequences of IR codes at the press of a button. Advertising Index Altronics...............................75-78 Ampec Technologies................. 83 Dave Thompson...................... 111 Digi-Key Electronics.................... 3 Emona Instruments................. IBC Hare & Forbes............................. 9 Jaycar............................ IFC,53-60 Keith Rippon Kit Assembly...... 111 Keysight Technologies........... OBC Subtractive Manufacturing Dr David Maddison details the history of manufacturing techniques involving devices like mills and lathes, through the early years of numerical control and onto the amazing modern CNC machines. These can create a wide array of shapes out of solid blocks of metal, timber, plastics or other materials with extreme precision and virtually no human labour. He also explains quite a few other modern subtractive manufacturing techniques that you may not be aware of. The Ol' Timer II We've presented plenty of clocks that give you sub-second accuracy. But sometimes you just need to know whether it's breakfast, lunch or dinner time. This innovative clock is cheap and easy to build, and it spells out the time in an easy-to-understand manner using a series of letters in different colours. Is it eight fifty nine and thirteen seconds? Nah, it's just before nine o'clock. Note: these features are planned or are in preparation and should appear within the next few issues of Silicon Chip. The July 2020 issue is due on sale in newsagents by Thursday, June 25th. Expect postal delivery of subscription copies in Australia between June 23rd and July 14th. LD Electronics......................... 111 LEACH PCB Assembly............... 5 LEDsales................................. 111 Microchip Technology.................. 7 Ocean Controls......................... 10 RayMing PCB & Assembly........ 11 Silicon Chip PDFs.................... 98 Silicon Chip Shop...........104-105 The Loudspeaker Kit.com......... 71 Vintage Radio Repairs............ 111 Wagner Electronics..................... 6 Notes & Errata DIY Oven Reflow Controller, April-May 2020; Low-distortion DDS (May 2019); and DSP Active Crossover & 8-Channel Parametric Equaliser, May-July 2019: The connections between IC11 and IC12 are shown incorrectly on the CPU circuit diagram, but are wired correctly on the PCB. The correct connections are: IC12 pins 2, 5 & 6 go to pins 5, 6 and 4 on IC11 respectively. In other words, SO connects to SDI_SDI2, SI to SDI_SDO2 and SCK to SDI_SCK2. 7-Band Mono or Stereo Equaliser, April 2020: Fig.7(c) is correct for the stereo version, but on the mono version, the negative end of the 100µF capacitor connects to chassis ground rather than V- (these two points are joined via JP2, so the effect is the same). Tunable HF Preamp with Gain Control, January 2020: the PCB and PCB overlay diagrams (Figs.2(a) & (b) on p42) show T3 rotated 180° compared to the correct orientation. The PCB photos show the correct orientation of T3. Super-9 FM Radio, November & December 2019: the parts list on p36 of the November 2019 issue called for 1m of 0.25mm diameter ECW for winding T1 & L6 while the winding instructions on p63 of the December issue say 0.125mm diameter. You can use either diameter; if using 0.25mm diameter, wind the first layer on T1 & L6 in two layers. If using 0.125mm diameter, you should be able to fit the turns in one layer. Arduino-based programmer for DCC Decoders, October 2018: there are some errors in the circuit diagram, Fig.1. The default state of the links between CON1 and CON2/3 have been swapped, ie, pin 6 of CON2 should connect to pin 6 of CON1, and pin 12 of CON3 should connect to pin 12 of CON1. Also, pin 6 of IC1 should directly connect to pin 7, not to pin 4. 112 Silicon Chip Australia’s electronics magazine siliconchip.com.au