Okay, question about BASIC electronics!

[KamPutty]

Hi all,

Hope you are all doing well.

I have a basic question, and just want to hear from someone else other then my brain (I question my brain these days!)

If I have a circuit and it says

#1. Connect pin 1 to +5v. Simple, I have a "+" on my DC power supply (set to 5v). I'll use that.

#2. Connect pin 2 to Ground. Now, I have a "ground" and a "-" on my power supply. They are NOT connected on the power supply. Using my multimeter, I know that I need to use the "-" as that gives my +5v.

NOW, my question is, what about "ground"? Should I connect my "-" and "ground" on my power supply and use that?

The reason for all this is I'm STILL trying to get my stupid 7219 working! I'm mostly (!!!!! ha haha haha hahah ahah funny!) sure it's a power issue, and they say connect pins x&y to ground...

I have ripped out all my wiring and rebuilt and still getting bizzare stuff...

thanks all!

~Kam (^8*

[asmallri]

If your power supply is a single ended power supply (generates just one output voltage), then you are describing a power supply with floating outputs. For example, if you were to measure the voltage between the +5v output and the case of a PC sitting near, but not physically connected to the power supply, then you could potentially measure hundreds of volts. If you connect the ground of the power supply to the -ve terminal of the power supply then the +5v output with at +5V wrt the power supplies negative terminal AND at +5V wrt ground. If you to now measure the voltage between the +5V terminal and the case of the PC you should measure +5V.

Occasionally (very rarely) you may have an application that requires a power supply that is capable of floating its outputs.

If on the otherhand you have a DUAL power supply, then + and - terminals are measured wrt the common ground. In other words, when set for 5 volts operation, the + terminal will be +5V wrt ground, the negative terminal will be -5V wrt ground and the voltage between the + and - terminals will be 10 volts.

If you are setting the output voltage to +5V using a meter internal to the power supply and are measuring +5V between the positive and negative terminal then it sounds like your power supply is the first type described with floating outputs. In this case I suggest connecting the power supply Ground and - terminals together.
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[mkent]

Do you have the commons on your boards connected togeather?

[PCM programmer]

Post the manufacturer and model number of your power supply.
One of us will look at the manufacturer's web page and explain
how to use it.

[KamPutty]

Brand: Kysan
Model: Hy3003D-2

http://www.kysanelectronics.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=KE&Product_Code=HY3003D-2&Category_Code=MO

When I set my voltage to 5.0, and check with multimeter by placing one end on "-" and one on "+", it says +5v on the multimeter.

Just to make sure my question does not get lost in the correct adjustment of the power supply, (in regards to the 7219), pins 4, and 9 are connected to Ground. Do we always assume that means "-"?

All I want to do is get this screwing 7219 working with my 8 7-seg LEDS for Jeebus sake!

Again, thanks for all the help...

~Kam (^8*
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[KamPutty]

[Mark]

Just use the + and - terminals (red and black) the green terminal is earth ground.

[mkent]

Common, ground, "-" can get confusing. I like to use +V, 0V, and -V. 0 (zero) volts is also called common. I went back to your previous post and see that you have different boards. I got a little confused about which is which but, you must have the 0V (common) connected between the boards or you don't have a return path for your signals. The cleanest way to do this is to use the same power supply for all the boards; run TWO wires to each board, a+5V and a 0V. Can you power your 7219 board from your pic demo board? Just find the +5V and 0V and jumper them over. I hope this is clearer than mud!

[KamPutty]