Silicon ChipIn & out of circuit LED tester - June 2021 SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Publisher's Letter: Semiconductor shortages are becoming serious / The right to repair
  4. Mailbag
  5. Feature: The Right to Repair (and Modify) by Dr David Maddison
  6. Project: Advanced GPS Computer - Part 1 by Tim Blythman
  7. Feature: The History of USB by Jim Rowe
  8. Project: Recreating Arcade Pong by Dr Hugo Holden
  9. Feature: The History of Videotape – Camcorders and Digital Video by Ian Batty, Andre Switzer & Rod Humphris
  10. Circuit Notebook: Building a better mousetrap by Bruce Boardman, VK4MQ
  11. Circuit Notebook: In & out of circuit LED tester by Graham P. Jackman
  12. Project: PIC Programming Helper by Tim Blythman
  13. Review: The New Arduino IDE 2.0 by Tim Blythman
  14. Project: Programmable Hybrid Lab Supply with WiFi – Part 2 by Richard Palmer
  15. Review: Weller T0053298599 Soldering Station by Tim Blythman
  16. Product Showcase
  17. Serviceman's Log: Trying to fix unbranded, generic equipment is frustrating by Dave Thompson
  18. PartShop
  19. Vintage Radio: 1940 RME Model 69 communications receiver by Fred Lever
  20. Ask Silicon Chip
  21. Market Centre
  22. Advertising Index
  23. Notes & Errata: Programmable Hybrid Lab Supply with WiFi, May 2021; Arduino-based Power Supply, February 2021; DIY Reflow Oven Controller, April-May 2020; Deluxe Touchscreen eFuse, July 2017
  24. Outer Back Cover

This is only a preview of the June 2021 issue of Silicon Chip.

You can view 0 of the 112 pages in the full issue.

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Items relevant to "Advanced GPS Computer - Part 1":
  • Advanced GPS Computer PCB [05102211] (AUD $7.50)
  • PIC32MX170F256B-50I/SP programmed for the Advanced GPS Computer [0510221A.hex] (Programmed Microcontroller, AUD $15.00)
  • DS3231 real-time clock IC (SOIC-16) (Component, AUD $7.50)
  • MCP4251-502E/P dual 5kΩ digital potentiometer (Component, AUD $3.00)
  • VK2828U7G5LF TTL GPS/GLONASS/GALILEO module with antenna and cable (Component, AUD $25.00)
  • Micromite LCD BackPack V3 complete kit (Component, AUD $75.00)
  • Matte/Gloss Black UB3 Lid for Advanced GPS Computer (BackPack V3) or Pico BackPack (PCB, AUD $5.00)
  • Firmware for the Advanced GPS Computer [0510221A.HEX] (Software, Free)
  • Advanced GPS Computer PCB pattern (PDF download) [05102211] (AUD $15.00)
  • Advanced GPS Computer box cutting diagram and lid dimensions (Panel Artwork, Free)
Articles in this series:
  • Advanced GPS Computer - Part 1 (June 2021)
  • Advanced GPS Computer – Part 2 (July 2021)
Articles in this series:
  • The History of USB (June 2021)
  • How USB Power Delivery (USB-PD) works (July 2021)
Items relevant to "Recreating Arcade Pong":
  • Mini Arcade Pong PCB [08105211] (AUD $35.00)
  • Pair of Signetics NE555Ns (Component, AUD $12.50)
Articles in this series:
  • The History of Videotape – Quadruplex (March 2021)
  • The History of Videotape - Helical Scan (April 2021)
  • The History of Videotape – Cassette Systems (May 2021)
  • The History of Videotape – Camcorders and Digital Video (June 2021)
Items relevant to "PIC Programming Helper":
  • 8-pin PIC Programming Helper PCB [24106211] (AUD $5.00)
  • 8/14/20-pin PIC Programming Helper PCB [24106212] (AUD $7.50)
  • Relay - EA2-5NU (Component, AUD $3.00)
  • PIC Programming Helper PCB patterns (PDF download) [24106211-2] (Free)
Items relevant to "Programmable Hybrid Lab Supply with WiFi – Part 2":
  • Programmable Hybrid Lab Supply Control Panel PCB [18104211] (AUD $10.00)
  • Programmable Hybrid Lab Supply Regulator Module PCB [18104212] (AUD $7.50)
  • 2.8-inch TFT Touchscreen LCD module with SD card socket (Component, AUD $25.00)
  • Software, manuals and laser templates for the Programmable Hybrid Lab Supply (Free)
  • Programmable Hybrid Lab Supply Control Panel PCB pattern (PDF download) [18104211] (Free)
  • Programmable Hybrid Lab Supply Regulator PCB pattern (PDF download) [18104212] (Free)
  • Drilling/cutting diagrams and front panel artwork for the Programmable Hybrid Lab Supply (Free)
Articles in this series:
  • Programmable Hybrid Lab Supply with WiFi – Part 1 (May 2021)
  • Programmable Hybrid Lab Supply with WiFi – Part 2 (June 2021)

Purchase a printed copy of this issue for $10.00.

In & out of circuit LED tester The idea for this circuit came to me when I was having difficulty locating faulty LEDs in a string, as used in an LED light bulb or infrared illuminator. Assuming that you’re prepared to spend the time, repairs can be made or good sections isolated to repair other units. Probing with a multimeter works, but you have to reverse the probes quite often. So I built this simple circuit around a 4093 quad schmitt trigger input NAND gate IC (one of my favourite chips for quick and dirty solutions). IC1d is configured as a simple oscillator. I have tied input pin 13 to ground via a 4.7MW resistor, so the siliconchip.com.au oscillator will not function until this pin goes high, accomplished with a simple touchpad made from a piece of Veroboard. Until this is activated, power consumption is virtually nil. When it does oscillate, it drives two gates in series out-of-phase (IC1c & IC1b), so their outputs continually swap polarities. These outputs are connected by the device under test (DUT) via a 22W resistor and LED2/LED3. These LEDs are connected in parallel with opposite polarity. LED2 and LED3 can only light when the DUT passes current. In the case of a functional device, the LED that turns on must have the same polarity Australia’s electronics magazine as the DUT. If both turn on, you have a short; if neither do, then there is an open circuit. A low resistance across the DUT could cause both LEDs to flash, but that is uncommon. The DUT can be connected by a simple socket or a pair of probes, used to check devices in-circuit. The accompanying breadboard diagram shows how you could build this circuit on a breadboard, or an IC style protoboard. Graham P. Jackman, Melbourne, Vic. ($80) June 2021  63