What is the difference between +5v and -5v?

[Hyde]

I apologize, as I am sure this a terribly newby question, but as the title states, what is the difference between +5v and -5v?

I'm asking this because on my Swimmer machine, the wire that lights up the coin door lamps is disconnected from the switcher. And I am assuming if it would go on either the +5v or -5v terminal. But I really don't know the difference between these two.

Any help would be great!

 

[bit_slicer]

Ground (GND) is zero volts. +5V is 5 volts above ground, and -5V is 5 volts below ground.

Not sure about the coin door light. You might need to refer to the schematic for which voltage it should be connected to.

 

[Hyde]

Ground (GND) is zero volts. +5V is 5 volts above ground, and -5V is 5 volts below ground.

Not sure about the coin door light. You might need to refer to the schematic for which voltage it should be connected to.

I've been looking for a Swimmer schematic but can't seem to find one online. If it helps, the +5v has "15 A" printed next to it as well. The -5v has a "1.5 A" printed next to it.

As you can see, electronics aren't really my thing yet. I'm trying to learn more piece by piece!

 

[bit_slicer]

The "A" means Amps. It's a measure of how much power is available on each voltage. More amps, more power (when the voltage is equal). Here's a Swimmer manual / schematic:

http://www.crazykong.com/manuals/Swimmer.man.pdf

 

[Hyde]

The "A" means Amps. It's a measure of how much power is available on each voltage. More amps, more power (when the voltage is equal). Here's a Swimmer manual / schematic:

http://www.crazykong.com/manuals/Swimmer.man.pdf

Well, I can't imagine some simple lamps would need much power going to them. Thanks for the link to the manual, though! Not sure why I couldn't find it earlier. I'll have to look through it to see if I can find what I need.

 

[demogo]

I don't know what I'm doing with schematics either but I did find a section that shows both +5v and -5v routed to the coin door.

I also found a reference to the bulbs being 6.3v bulbs or somesuch.

My guess is that they run off of +5. I've only really heard of -5v being used for sound on some games and I'm really not sure why it would be routed to the coin door at all.

I believe on at least some of my games they are using +12v for the coin lights.

 

[modessitt]

5v-(-5v)=10v...

 

[jay]

I have found what I think is the best explanation for this. In reality, it's something you "know" or figure out when you taking "applied electronics" or something like that. It an oxy moron without the "Oxy".

Hard to explain

http://www.answerbag.com/q_view/4655

The first comment on the answer is the best.

It's a giant mind f**k in reality. I fight with this type of crap all day at work.

It will make you "old" real quick

 

[Pac-Fan]

Well, I can't imagine some simple lamps would need much power going to them.

Actually that's a common misconception. Incandescent lighting actually pulls quite a few amps in comparison to logic circuits.

Most lamps pull .2 to .3 amps per lamp. You can look up the draw online from many places, but pinball sites are usually where the best lists can be found. Think of the heat these put out and equate that to power used.

Therefore a coin door with 2 lamps could pull as much as .6 amps. (This is why Bally/Midway cocktails have an extra transformer winding and extra fuses specifically for the lighting in the cocktail (6 total lamps, 2 per player per CP and 2 for the coin door) compared with theiur upgrights). If combined with the +12V line from a switcher that also feeds your board for audio and the switcher only puts out 1 amp on the 12 volt line, you might overload it.

Now at +5V, most switchers put out 7-15 amps on the +5v and most boards only pull 5-10 amps. However the -5V line usually is 1/2 an amp to 1 amp, so you do need to be careful. -5V was used for some audio amplifiers and other special circuitry; though most boards only use +5V logic, +12V audio.


As a comparison, myTime Pilot board pulls 3 amps on +5, and a 48-in-1 board I just tested today pulls .6 amp on +5. That's just 2 lamps of power.

 

[Hyde]

Ok, I think I am going to hook it up to the +5v conenctor. Thanks for all the reponses! The coin door lamps on my Swimmer shall light up once more!

 

[ELutz]

Every Centuri game I've ever worked on (too many to count)....all ran the coin door lamps off the -5VDC lug of the switcher. Honestly, you can use either (5VDC or -5VDC). If your switcher is pumping 15A on the 5VDC rail....that's more than enough to run the bulbs and the motherboard. For the record (and, if memory serves me correctly)....44 bulbs pull .25 amps....their 47 counter-part pull .15 amps.

I assume Centuri used the -5VDC line (as opposed to the 5VDC line) to keep the coin door light voltage separate from the main logic voltage.

Edward

 

[metahugh]

Every Centuri game I've ever worked on (too many to count)....all ran the coin door lamps off the -5VDC lug of the switcher. Honestly, you can use either (5VDC or -5VDC). If your switcher is pumping 15A on the 5VDC rail....that's more than enough to run the bulbs and the motherboard. For the record (and, if memory serves me correctly)....44 bulbs pull .25 amps....their 47 counter-part pull .15 amps.

I assume Centuri used the -5VDC line (as opposed to the 5VDC line) to keep the coin door light voltage separate from the main logic voltage.

Edward

That would make sense because I have seen lamp sockets become dead shorts and wreak all kinds of havok. Sounds like a good design to separate them... although I would expect this to be more of a problem with Pinballs than video games.

 

[YellowDog]

If you are concerned, pick up some LED bulbs. You can get them in almost every base style now and they draw almost no current. Check in the pinball forum for some links to mail order sites that sell them. I run them off the -5V in my JAMMA cabs that don't have a 6.3VAC circuit becuase I replaced the big transformer with a switcher.

ken

 

[hindered]

5v-(-5v)=10v...

I wanted to post this.

 

[Hyde]

Every Centuri game I've ever worked on (too many to count)....all ran the coin door lamps off the -5VDC lug of the switcher. Honestly, you can use either (5VDC or -5VDC). If your switcher is pumping 15A on the 5VDC rail....that's more than enough to run the bulbs and the motherboard. For the record (and, if memory serves me correctly)....44 bulbs pull .25 amps....their 47 counter-part pull .15 amps.

I assume Centuri used the -5VDC line (as opposed to the 5VDC line) to keep the coin door light voltage separate from the main logic voltage.

Edward

I can't see why Swimmer would be any different than other Centuri games. I think I may just need to switch it back to -5v now. The lamps are #47. Besides, the +5v has 15 amps next to it as well. That seems way too high for coin door lights.

 

[mrbill08]

+1

Bill

I wanted to post this.

Quote:
Originally Posted by modessitt
5v-(-5v)=10v...

 

[demogo]

I can't see why Swimmer would be any different than other Centuri games. I think I may just need to switch it back to -5v now. The lamps are #47. Besides, the +5v has 15 amps next to it as well. That seems way too high for coin door lights.

Hyde,

That's the max amps that the power supply puts out for that voltage. That's not really related.