1. Practical High Voltage Power Supplies Ian White, GM3SEK Click to step through the presentation

2. Practical High Voltage PSUs Safety + Reliability Practical circuits and components

3. Safety + Reliability Thousands of amateurs use HV safely, every day. So can you! But your first big mistake will be your last, so… Always think about what you’re doing and you’ll be fine. DON’T MAKE MISTAKES!

4. Safety + Reliability Good safety habits: Multiple barriers against failures and accidents. NEVER be only one fault away from danger. ALWAYS unplug from the mains. ALWAYS discharge HV circuits before touching. Multiple earth bonding – very important. ALWAYS be thinking what could possibly go wrong… and then prevent it! 1. Defence in Depth.

5. Safety + Reliability Good safety habits: 1. Defence in Depth. 2. Build safety into hardware. Don’t rely on ‘being careful’… because one day you will drop your guard. Use good quality components and construction. Greatest risk when testing and repairing. Use safety covers inside (clear acrylic sheet).

6. Safety + Reliability Make these into your way of life: 1. Defence in Depth. 2. Build safety into the hardware. 3. Don’t ever stop thinking!

7. Safety + Reliability Reliability – for DX and contesting Building reliability into the hardware : Good quality components and construction. Under-run all components. Check all component ratings. Use cooling fans.

8. Practical High Voltage PSUs Safety + Reliability Practical circuits and components

9. Circuits and Components

10. Mains

11. Circuits and Components Transformer

12. Circuits and Components Rectifiers + capacitors

13. Circuits and Components HV+ output

14. Circuits and Components HV-minus return

15. Circuits and Components

16. Mains Circuits and Components

17. Transformer

18. Circuits and Components Transformer

19. Circuits and Components Transformer

20. Circuits and Components Transformer

21. Circuits and Components

24. Rectifiers + capacitors Bridge rectifier is best! About 30uF

25. Circuits and Components HV+ output Surge limiting resistor (“Glitch resistor”) HV socket Coaxial SAFE connector! Earth bonding

26. Circuits and Components HV-minus return Why a separate HV-minus return? Chassis earth

27. Circuits and Components HV-minus return Anode current Grid current

28. Circuits and Components HV-minus return 5-pin XLR socket: HV-minus (duplicated) Earth (duplicated) HV control input Connector shell also earthed. Important safety precautions. HV won’t turn on unless this is plugged in. Chassis earth

29. Circuits and Components

30. Practical High Voltage PSUs Safety + Reliability Practical circuits and components For more details… Radcom January-February-March 2009 The ‘In Practice’ website: http://tinyurl.com/inpractice

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