Home
JAQForum Ver 20.06
Log In or Join  
Active Topics
Local Time 12:35 29 Mar 2024 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Microcontroller and PC projects : Picomite VGA design #2 confusion

Author Message
Rickard5

Guru

Joined: 31/03/2022
Location: United States
Posts: 328
Posted: 10:19pm 02 Oct 2022
Copy link to clipboard 
Print this post

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
 
lizby
Guru

Joined: 17/05/2016
Location: United States
Posts: 2989
Posted: 10:45pm 02 Oct 2022
Copy link to clipboard 
Print this post

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
 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 1721
Posted: 10:52pm 02 Oct 2022
Copy link to clipboard 
Print this post

"the offset hole is definitely connected to ground,"

Vcc perhaps? The circuit shows that.
 
lizby
Guru

Joined: 17/05/2016
Location: United States
Posts: 2989
Posted: 12:35am 03 Oct 2022
Copy link to clipboard 
Print this post

  phil99 said  "the offset hole is definitely connected to ground,"

Vcc perhaps? The circuit shows that.


Oh, you are right--3V3. I assumed too much from the SGD silk screen.
PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed
 
Rickard5

Guru

Joined: 31/03/2022
Location: United States
Posts: 328
Posted: 01:34am 03 Oct 2022
Copy link to clipboard 
Print this post

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
 
Frank N. Furter
Guru

Joined: 28/05/2012
Location: Germany
Posts: 812
Posted: 05:23pm 03 Oct 2022
Copy link to clipboard 
Print this post

Hi RickardS,

I have used TN0702N3-G:



Frank
 
Rickard5

Guru

Joined: 31/03/2022
Location: United States
Posts: 328
Posted: 07:56pm 03 Oct 2022
Copy link to clipboard 
Print this post

  Frank N. Furter said  Hi RickardS,

I have used TN0702N3-G:

Frank


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
 
Frank N. Furter
Guru

Joined: 28/05/2012
Location: Germany
Posts: 812
Posted: 06:36am 05 Oct 2022
Copy link to clipboard 
Print this post

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
 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 1721
Posted: 11:37am 05 Oct 2022
Copy link to clipboard 
Print this post

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.
 
Print this page


To reply to this topic, you need to log in.

© JAQ Software 2024