I'm just putting together some PSU 'kits' from eBay (notorious audiotek) and came across something unfamiliar.
There are two connectors (labelled TP1,TP2) which are connected to the ends of the fuse- this is on the DC side at the outputs. Included in the 'kit' is a 10 ohm resistor which the (fuzzy) pic in the eBay ad shows connected between TP1 & TP2.
So there is a 10 ohm resistor in parallel with the fuse? What's the point?
I'd appreciate any 'enlightenment' on this- mostly to satisfy my curiosity- the PSUs seem to work fine.
Thanks
John
There are two connectors (labelled TP1,TP2) which are connected to the ends of the fuse- this is on the DC side at the outputs. Included in the 'kit' is a 10 ohm resistor which the (fuzzy) pic in the eBay ad shows connected between TP1 & TP2.
So there is a 10 ohm resistor in parallel with the fuse? What's the point?
I'd appreciate any 'enlightenment' on this- mostly to satisfy my curiosity- the PSUs seem to work fine.
Thanks
John
Hi,
the TP either side of the 10r allows you to measure the current during testing.
The 10r is not a good way of limiting fault current. It generally takes too long to rupture if large fault currents flow and drops too little voltage if lower fault currents flow.
A Variac or current limited lab PSU or mains light bulb tester will all do a better job of limiting/preventing catastrophic failure if there is a circuit and/or component fault.
the TP either side of the 10r allows you to measure the current during testing.
The 10r is not a good way of limiting fault current. It generally takes too long to rupture if large fault currents flow and drops too little voltage if lower fault currents flow.
A Variac or current limited lab PSU or mains light bulb tester will all do a better job of limiting/preventing catastrophic failure if there is a circuit and/or component fault.
Star and Andrew-AndrewT said:
A Variac or current limited lab PSU or mains light bulb tester will all do a better job of limiting/preventing catastrophic failure if there is a circuit and/or component fault.
Thanks for the responses.
Andrew- I've got 'all of the above' here and use them as appropriate when firing up gear for the first tests. All good advice.
The 10Rs went into the parts box.
Cheers
John
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