Modification of the Radioditty charger with "TP5100" card at $ 2.

VK3KYY
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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by VK3KYY » Wed Jan 29, 2020 10:55 pm

VK3KYY wrote:
Wed Jan 29, 2020 10:55 pm
m1dyp wrote:
Wed Jan 29, 2020 10:50 pm
VK3KYY wrote:
Wed Jan 29, 2020 10:32 pm
Yes.

I think that would be OK.

I'm not really sure the diode is necessary. They normally only fit diodes in situations where people can apply the power the wrong way around e.g where people can insert a battery the wrong way around.

But in this case, it seems unlikely that the power supply would ever input voltage with the polarity reversed
thanks roger, i was concerned about.....

DG1YFX wrote: ↑Wed Jan 29, 2020 10:02 pm
The diode protects the TP5100 from sudden death in case you switch off the power and the inductor produces a uncontrolled reverse polarity. I killed quite a few boards until I realized this.
73s Jens


dont want to keep buying boards when they take a week to get here :mrgreen:

Ah.

In that case normally the diode would be in parallel with the coil to quench the reverse voltage transient.

Its standard practice to do this on relay's

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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by VK3KYY » Wed Jan 29, 2020 10:56 pm

VK3KYY wrote:
Wed Jan 29, 2020 10:55 pm
VK3KYY wrote:
Wed Jan 29, 2020 10:55 pm
m1dyp wrote:
Wed Jan 29, 2020 10:50 pm


thanks roger, i was concerned about.....

DG1YFX wrote: ↑Wed Jan 29, 2020 10:02 pm
The diode protects the TP5100 from sudden death in case you switch off the power and the inductor produces a uncontrolled reverse polarity. I killed quite a few boards until I realized this.
73s Jens


dont want to keep buying boards when they take a week to get here :mrgreen:


Ah.

In that case normally the diode would be in parallel with the coil to quench the reverse voltage transient.

Its standard practice to do this on relay's

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DG1YFX
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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by DG1YFX » Wed Jan 29, 2020 11:03 pm

A week? You lucky devil. :lol: As I order in China direct it takes about 4 weeks. But then it is 2$ for 4 of them. It took me some time to realize why these things were so delicate to handle. When I switched off the power supply and switched it on again, no problem. But when I pulled the plug directly from the charger, next time, the board was dead. With the diode, they live happiliy ever after. Maybe some of the boards are fakes without the proper protection diodes inside the chip. Who knows? The TP5100 specs sheet says the chip is protected against everything. :roll:

73s,
Jens

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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by VK3KYY » Wed Jan 29, 2020 11:21 pm

DG1YFX wrote:
Wed Jan 29, 2020 11:03 pm
A week? You lucky devil. :lol: As I order in China direct it takes about 4 weeks.
Its the same here.

Its been taking longer and longer for components like this to arrive from China.

If I buy from AliExpress, I try to find a vendor who ships via ePacket, which in theory should be a bit like normal post and only take 1 to 2 weeks, but it costs a bit extra and often I find it still takes 3 to 4 weeks, as there is no guarantee of the 1 to 2 weeks , best case, delivery time :-(

Even buying from local vendors on eBay, is often a scam, as they are just proxies for vendors in China, and it takes just as long for things to arrive.
On eBay I check whether the vendor has their post code in their address, and I only order from those, and not the vendors that list their address as "Australia Australia"

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m1dyp
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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by m1dyp » Wed Jan 29, 2020 11:42 pm

DG1YFX wrote:
Wed Jan 29, 2020 11:03 pm
A week? You lucky devil. :lol:
yeah uk poster for china ebayer, we have a few like that here
73 de Ken :D

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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by F1CXG » Thu Jan 30, 2020 6:44 am

Diagram modified for a useful use of the diode in "freewheeling"
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.
SCH2.jpg
SCH2.jpg (100.94 KiB) Viewed 416 times
73 de Thierry ;)

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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by VK3KYY » Thu Jan 30, 2020 6:48 am

Thanks Thierry

That looks much more logical

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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by m1dyp » Thu Jan 30, 2020 6:58 am

Thanks Thierry
73 de Ken :D

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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by F1CXG » Thu Jan 30, 2020 7:39 am

And here is the aspect after resumption of some welds with Photoshop :mrgreen:

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Image
73 de Thierry ;)

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Re: Modification of the Radioditty charger with "TP5100" card at $ 2.

Post by F1RMB » Thu Jan 30, 2020 8:03 am

F1CXG wrote:
Thu Jan 30, 2020 7:39 am
And here is the aspect after resumption of some welds with Photoshop :mrgreen:

.
Image
Is Adobe manufacturing soldering irons ? ROTFL
73 de Daniel.

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