Step 17: Build the Power Regulator
What you need:
Soldering Iron
Medium-sized piece of perfboard
7805 Regulator (From the RF box)
Heatsink (You can use the one from the RF box if you like)
1,000uf Capacitor
Two 0.1uf Capacitors
1 - 10uf Capacitor
1N4001 Diode
Before we start, you have to understand what a regulator is and what it does. A regulator takes any voltage above a certain amount and drops it to a specified voltage. For example, the 7805 regulator we are using takes anything from 7.5 - 36 volts and drops it to 5v, which is what we need for the NES. The extra energy is given off as heat, so you need something called a heatsink. A heatsink attaches to the regulator and dissipates the heat coming from it. Without a heatsink, the regulator would burn itself out. The more surface area a heatsink has, the better it takes heat away from the regulator. You can use the one from the RF box.
Note: A 7805 needs at least 7.5v to run, so you must make sure your batteries are at least that much.
SOLDERING THE BOARD
Anyways, the schematic for the regulator is in the first picture. It has a drawing of the regulator and its pins. Pin 1 is the voltage in, pin 3 is ground, and pin 2 is five volts out.
The reason for all the capacitors is to smooth out any ripples in the voltage coming from the batteries. C1 can be anything from 250uf to 1,000uf, and smooths the voltage coming straight from the battery. I just used what I had lying around, which was a 250uf cap. C2, C3, and C4 smooth out the current coming from the regulator.
Some capacitors can probably be excluded, like C1 (1,000uF) and C4 (.1uF). Also, C1 could be around 470uF as well. The values aren't all that critical.
OPTIONAL
The diode, D1, is not necessary. It is only there to drop the voltage by about 1v, because I found that the regulator really gave out 6v. The NES will be fine running at 6v, but I just wanted to be safe.
I used a 3-pin connector for my regulator board, because I wanted it to be removable.You don't have to, but it does make things easier.
See above note about capacitors.
TESTING THE BOARD
You can finally test your NES! Solder the output pin on your regulator (+5v out) to the 5v in on the NES, and attach ground. Use a couple of alligator clips to hook it up to a TV. Plug in a cartridge (Make sure it's facing the right way!), add the battery, and try it out! If it doesn't work, don't worry. Try switching the alligator clips for video and ground. If it still doesn't work, check all your connections. Make sure there are no shorts anywhere. It is highly unlikely you fried your NES. Once you get it working, set it aside and get out the screen you ordered.
Soldering Iron
Medium-sized piece of perfboard
7805 Regulator (From the RF box)
Heatsink (You can use the one from the RF box if you like)
1,000uf Capacitor
Two 0.1uf Capacitors
1 - 10uf Capacitor
1N4001 Diode
Before we start, you have to understand what a regulator is and what it does. A regulator takes any voltage above a certain amount and drops it to a specified voltage. For example, the 7805 regulator we are using takes anything from 7.5 - 36 volts and drops it to 5v, which is what we need for the NES. The extra energy is given off as heat, so you need something called a heatsink. A heatsink attaches to the regulator and dissipates the heat coming from it. Without a heatsink, the regulator would burn itself out. The more surface area a heatsink has, the better it takes heat away from the regulator. You can use the one from the RF box.
Note: A 7805 needs at least 7.5v to run, so you must make sure your batteries are at least that much.
SOLDERING THE BOARD
Anyways, the schematic for the regulator is in the first picture. It has a drawing of the regulator and its pins. Pin 1 is the voltage in, pin 3 is ground, and pin 2 is five volts out.
The reason for all the capacitors is to smooth out any ripples in the voltage coming from the batteries. C1 can be anything from 250uf to 1,000uf, and smooths the voltage coming straight from the battery. I just used what I had lying around, which was a 250uf cap. C2, C3, and C4 smooth out the current coming from the regulator.
Some capacitors can probably be excluded, like C1 (1,000uF) and C4 (.1uF). Also, C1 could be around 470uF as well. The values aren't all that critical.
OPTIONAL
The diode, D1, is not necessary. It is only there to drop the voltage by about 1v, because I found that the regulator really gave out 6v. The NES will be fine running at 6v, but I just wanted to be safe.
I used a 3-pin connector for my regulator board, because I wanted it to be removable.You don't have to, but it does make things easier.
See above note about capacitors.
TESTING THE BOARD
You can finally test your NES! Solder the output pin on your regulator (+5v out) to the 5v in on the NES, and attach ground. Use a couple of alligator clips to hook it up to a TV. Plug in a cartridge (Make sure it's facing the right way!), add the battery, and try it out! If it doesn't work, don't worry. Try switching the alligator clips for video and ground. If it still doesn't work, check all your connections. Make sure there are no shorts anywhere. It is highly unlikely you fried your NES. Once you get it working, set it aside and get out the screen you ordered.
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I do have one last question before I start actually soldering the regulator though. I see that your regulator has what look like polyester film capacitors, I'm assuming those are the two 0.1 uF capacitors from the diagram, but they are not polarized, correct? I ask because I have two 0.1uF capacitors that are polyester film and look exactly like the ones in your picture and I was curious if they would work for the regulator even though they don't seem to be polarized?
So I get that you have pin 2 leading to your NES, but does that mean that you have the battery running directly to pin 1 and then have pin 3 (the ground) lead to your screen, or do you wire the battery to your screen first and then have a wire from your screen to pin 1 (and then ground the wire from pin 3 to the mother board like the video amp)? I ask because if you have two output wires leading from the battery, (one to the screen and one to the NES) then wouldn't the current would choose whichever path was shorter ( this is according to my third grade knowledge of circuitry)?
You can connect whatever you like to the battery and it will power all of it. Also, ground is universal and goes to everything. If everything does not have ground, things won't work right. I'm glad you're asking questions! If I'm being a little vague or you need a better explanation, please say so!
Also, the diagram shows the ground wire leaving in two directions, so I assume that answers my previous question about powering the screen, as one wire is grounded to the NES board and the other would lead back to the screen and battery, correct?
http://www.wjoe.com/circuit_symbols.htm
quick question, could I charge this battery like a normal battery?
I'm not sure if it has the charging circuit built in.
I would recommend building your own (if you can). National Semiconductor (www.national.com) has a good calculator which allows you to pick your specs (?V in, 8.5V out, 5.3A - might want to call it 5.5 or 6A) and then designs the schematic etc for you. That's how you'd make one yourself.
A quick search (of digikey) yielded no reasonably-priced results for pre-built supplies.
If you want to continue searching, keywords: DC-DC converter, Switching Regulator