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Forum Index : Microcontroller and PC projects : Picomite VGA design #2 confusion
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Rickard5 Guru Joined: 31/03/2022 Location: United StatesPosts: 328 |
Hi everybody, I'm building a new Picomite VGA Design #2, I'm thinking it'll be cool to take with me camping :) any how I have both the BST72A and TN0702N3-G transistors specified as Q1 & Q2 in the BOM for the KB interface, the problem I have is the transistors all have 3 legs and the board's have 4 Holes for each, the Question is with 3 holes do I use. Do I use the upper or lower center hole ? I Know it's Probably Obvious, but the children call me famous What the old men call insane I turned the volume on the monitor to max and could hear sound. Thanks Stanleyella |
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lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 2989 |
It may have been designed to take either the in-line format or the tripod format. On the back of the board, are the middle and offset holes connected? In any case, the offset hole is definitely connected to ground, so if you use that and have S and D right, then you should be good. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 1721 |
"the offset hole is definitely connected to ground," Vcc perhaps? The circuit shows that. |
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lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 2989 |
Oh, you are right--3V3. I assumed too much from the SGD silk screen. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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Rickard5 Guru Joined: 31/03/2022 Location: United StatesPosts: 328 |
Cool Thanks Guys so I should just be ok with putting in the 3 pins straight across ? I turned the volume on the monitor to max and could hear sound. Thanks Stanleyella |
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Frank N. Furter Guru Joined: 28/05/2012 Location: GermanyPosts: 812 |
Hi RickardS, I have used TN0702N3-G: Frank |
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Rickard5 Guru Joined: 31/03/2022 Location: United StatesPosts: 328 |
Hey Frank I ended up using the TN0702N3-G too. can I ask what you used for D1 MBR360G?, I ordered the MBR360G from 3 different vendors and always got a Diode with leads too thick too fit though PCB. So my solution was to rob some Machined pins fro m a socket and solder them in then solder Diode to the Pins! I turned the volume on the monitor to max and could hear sound. Thanks Stanleyella |
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Frank N. Furter Guru Joined: 28/05/2012 Location: GermanyPosts: 812 |
Hi, I had the same problem. 3A are quite a lot. I used a 1N5817 with 1A. All 3A diodes had connections too thick for me as well. Frank |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 1721 |
The benefit of Schottkey diodes is a lower Vf than standard diodes but offsetting that is a higher resistance for a given current rating. An over rated one is used for its lower resistance. However it won't matter if the supply is a little high and the load is low. |
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