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Advertising Index Altronics...........................loose insert Dyne Industries................................ 7 Embedded Logic Solutions.............. 8 Emona Instruments........................ 11 Geoff Coppa................................. 103 Grantronics.................................. 103 Harbuch Electronics..................... 101 Hare & Forbes............................ OBC Instant PCBs................................ 103 Ask SILICON CHIP DOWNLOAD OUR CATALOG at . . . continued from p102 www.iinet.net.au/~worcom circuitry based on an Analog Devices AD8495 precision instrumentation amplifier. MPPT operation misunderstood According to the schematic supplied for the MPPT Solar Charge Controller in the March 2012 issue, there is no voltage conversion that is characteristic of a MPPT controller. I believe it is not really an MPPT device. Just having a bit of smarts does not qualify. (J. H., via email). • The MPPT operation of this project was fully explained in the first article, in the February 2011 issue. The voltage WORLDWIDE ELECTRONIC COMPONENTS PO Box 631, Hillarys, WA 6923 Ph: (08) 9307 7305 Fax: (08) 9307 7309 Email: worcom<at>iinet.net.au conversion is done by switching the Mosfet at 31.25kHz under the control of the micro. There is a brief mention of this PWM (pulse width modulation) in the caption of the circuit diagram on page 92 of the March 2012 issue. So the microcontroller is actually providing two functions: MPPT for the solar panel and 3-stage charging for the battery. If you would like a copy of the February 2011 issue, we can supply it for $12 including postage and packSC ing. Notes & Errata Ultra-LD Mk.3 200W Amplifier Module, Pt.2 (August 2011): the Dynamic Headroom specification was calculated incorrectly. It should be 1dB for 8Ω loads and 1.3dB for 4Ω loads. The Music Power and Slew Rate figures are correct. USB MIDIMate (October 2011): the 18-pin IC socket specified in the parts list should be a 20-pin IC socket. Crystal DAC (February 2012): the original PCB has the trimpots rotating in the opposite direction to that stated in the article, ie, clockwise rotation decreases the quiescent current rather than increasing it. A modified PCB file has been uploaded to the website which fixes this prob104  Silicon Chip lem. Constructors using the original PCB should rotate both trimpots fully clockwise before applying power for the first time. 1.5kW Induction Motor Speed Controller (April-May 2012): the PCB overlay diagram (May, p69) shows two 270Ω resistors below IC3 which should have been labelled 100Ω (their value is wrong in the parts list too). Also, the circuit diagram (April, p22) shows the three pull-up resistors for the pins of CON5 (two 4.7kΩ & one 1.5kΩ) all connected to pin 1 of CON4. They are actually connected to the +3.3V rail. Finally, the Altronics catalog number for the 470μF 400V capacitors in the parts list is incorrect. It should be R5448. Jaycar ................................ IFC,49-56 Keith Rippon................................. 103 Kitstop............................................ 45 LED Sales.................................... 103 LHP.NET.AU................................. IBC Microchip Technology..................... 15 Mikroelektronika............................. 23 Oatley Electronics.......................... 31 Ocean Controls................................ 6 Quest Electronics......................... 103 Radio & Hobbies DVD.................... 45 Reality Design.................................. 7 Red Button Technologies................. 5 RF Modules.................................. 104 Roc-Solid......................................... 9 Sesame Electronics..................... 103 Silicon Chip Binders................ 72,103 Silicon Chip Bookshop................... 88 Silicon Chip Order Form................ 97 Silicon Chip Partshop..................... 96 Silicon Chip Subscriptions............. 89 Siomar Battery Engineering...... 3,103 Splat Controls.............................. 103 Truscotts Electronic World............ 103 Verbatim Lights.............................. 81 Wiltronics....................................... 10 Winradio Communications............. 25 Worldwide Elect. Components..... 104 siliconchip.com.au