Hi folks,
A couple people have made recent posts mentioning low cost power supplies for bread boarding and bench development. Thought I'd share a supply that has been working well for me and see what others may be using as well. While I have a variety of decent bench supplies, I occasionally want a simple and low cost supply that I can dedicate to a given bread board project for a period of time… or plywood board in some cases… While I can often do without current limiting, excellent load regulation or superior low noise, I virtually always want a single power switch. Low cost is nice as well... A case in point requiring +35 VDC, +70 VDC and -210 VDC… all at low current: <https://lh3.googleusercontent.com/-rXXE5nPd7ng/WsF9AEQO8tI/AAAAAAAAFvM/_yMKhKJMNl4q3yKwaNr0A-FyDKhDK-UfACLcBGAs/s1600/breadboard.JPG> Shown above are three Chinese DC-DC Boost converters to the rear under blue painter’s tape. These three supplies are run off a single positive 12VDC supply with trin-pot adjustable bipolar outputs. Painter's tape? It's a bread board and NOT left running unattended! Cautions also apply when working with HV... the photo above is not a great example of good bench practice! To mitigate, I touch wires only after the supplies are powered off, disconnected from the source supply and allowed to discharge for 45 seconds or so. Here's one of the three supplies... photo from the web... <https://lh3.googleusercontent.com/-n00uC9Dki_Y/WsF9I7wOBmI/AAAAAAAAFvQ/DjQ6zNODUGcBl-zvsBpbIaEDKxLgD7wqACLcBGAs/s1600/supply.png> The stock specification on these is 8VDC to 32VDC input, +/-45VDC to +/-390VDC output. These cost around $6.04/each plus $1.85 shipping… just under $20 for three supplies delivered. AND a few weeks waiting for delivery. (Suggestion… If these sound good to you, order a few now and save yourself the wait when the next project comes round! They take very little space in the spare parts file.) Here’s one of many similar listings for these supplies: https://www.ebay.com/itm/322374659518 The careful reader may have noticed that I needed +35VDC for the project above and that the supplies are rated for a low end of +/-45VDC… I changed the circled resistor below from the stock value of 5.78K to 28.7K. This dropped the low end output from around 41VDC to 31VDC. A caution: Please be careful setting high voltage outputs on this modified supply as the upper limit has been moved… I marked the modified converter for lower voltage and will limit it to around 100V max out. I’ve blown similar supplies when running them near their upper limits. As a result, I now de-rate these and similar units by at least 10% for both voltage and current. I saved the original 5.78K/0603 and an 18K/0805 part I tried… These extra parts are boxed it the photo below and hung off a large terminal block connection for future use if needed. <https://lh3.googleusercontent.com/-PQUsl7ruj0g/WsF-P65fzUI/AAAAAAAAFvg/Rrk3yiAbHXsA5pvEbFNy5J_JReN8TR7pQCLcBGAs/s1600/modification.jpg> Sooo... What supplies do YOU use? Best regards, Bob -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/2082c90f-6710-4dd0-8141-3033dc47214d%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
