| The Shop > Electronics & IC Programing |
| Digital oscilloscope project/kit |
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| John Rudd:
There are a couple of reasons for putting the fuse in the pri, 1) it will blow if theres a short on the secondary or primary side...... 2) the big 2200mfd cap will appear as a short circuit for a brief period as it charges up....depending on the fuse size, would cause it to blow... |
| RobWilson:
--- Quote from: Bluechip on December 31, 2015, 11:15:18 AM --- Hence a 12 0 12 12VA tranny will be quite OK in practice even if your wretched simulator doesn't think so. Dave --- End quote --- Whats the poor thing done to you :lol: :lol: I will try both . The transformers I have are 3VA --- Quote from: John Rudd on December 31, 2015, 11:17:49 AM ---There are a couple of reasons for putting the fuse in the pri, 1) it will blow if theres a short on the secondary or primary side...... 2) the big 2200mfd cap will appear as a short circuit for a brief period as it charges up....depending on the fuse size, would cause it to blow... --- End quote --- Its moved John :thumbup: Rob |
| John Rudd:
I've not been a big fan of sims.....much prefer to see what happens if approach..... Best thing to do Rob, is lash up the circuit on some Vero board with the 12 v transformer and measure what comes out..... If the usual approach of V ac in x 1.414 is applied and subtract the Vdrop for the diodes, the actual output is usually different to the theoretical calculated..... :coffee: The meter never lies.... :lol: |
| RobWilson:
I have attached two files showing the regulator output voltages , one with an input of 12-0-12 and the other 18-0-18 The 12-0-12 gives out less than 12 volts :scratch: Rob |
| Bluechip:
3VA ??? :bugeye: Like running 'em lean 'n mean eh ? :D Don't forget to phone up National Grid PLC before you power up. Tell 'em to brace themselves ... :lol: :lol: Found the schematic: The bottom bit, ie. + / - 12V was the original I built. I've added your 5V & 9V, think it's OK ... :scratch: I've upped C1 & C5 a bit to reflect greater load but I don't think its really required for your application. |
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