|31st March 2008, 11:13 AM||#1|
Elektor Crescendo from cadsoft.de
I am in process of building the Elektor Crescendo amplifier.
I used the eagle board availalable at ftp://ftp.cadsoft.de/eagle/userfiles...s/diycres.brd.
following is a brief story about my project.
This is my first project from scratch(etching the board).
I some have managed to collect the all matching components as per the board and few near matching components.
I used all matching active components and few near matching passive components.
I am experimenting with low power version by using single pair of mosfets j162/k1058 from hitachi.
My multimeter shows on the baord as 28 to 29 plus and minus volts.
when I first powered the board and I did not dare to connect the power mosfets did some some simulations at mje340/mje350 bjit's,I found ac voltage flactuation from .02 to 13 volts then proceeded to power the mosfets thinking my mosfet driver stage is perfect.
When I powered the output stage the output resistors were heating to cup a tea.
Then I disconnected resistors to the output both sides N and P channel and checked the dc voltage and I realized I bought a blown MOS k1058 which was giving 22 volts when no gate voltage is applied.
Then I bought another k1058 which looked a genuine and powered ,this time every thing looked stable no too much heat dissipation.
But my problem is my mosfets does not amplify.
From my multimeter I see the gate and source volatges are same .
Did I again blowed the mosfets ?.
suggessions are appriciated, I am behind it for last 15 days(day and night).
|7th April 2008, 06:42 PM||#2|
Found where I am commiting mistake
It looks I asked a dry query or a repeating story,no one responded to my last post.
Any way I found where I was doing the mistake.
I rectified it by a suggession found from the diyers in some forum.
I was switching the fets to the maximum, when I am powering my board by biasing at 0ohms and consequently frying the fets.
When I adjusted bias to some 500ohms my board became stable.
Now I am able to get amplified signal but I still have a query.
I could get peak 1 amp at 10hms from my prototype but I could not see any huge variation of signal at the source, while I could see a vairiation of 0 to 13 mv at gate. And the same volatge is showing in my multimeter 0-13 v.
How much wattage I am getting from my board ? how can I caliculate this ?.
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