Resistors for Custom Regulators

[Ikeprodigy]

Where's the best place to get the listed resistors for custom regulators? (87.2k, 33.8k, 1.89k, 353)

I'm having a hard time finding some for an affordable price.

If there aren't any resistors with the exact value, what are the best combinations to put in series?

Links would be appreciated!

 

[Gman]

These are the resistors I use. I prefer to get them from digikey but ebay or other online sources are fine too.

3x PTH08080 23.03 https://www.digikey.com/product-detail/en/texas-instruments/PTH08080WAH/296-20432-ND/724048
6x 100uf Cap 0.75 https://www.digikey.com/product-det...tronic-components/ECE-A1AKS101/P963-ND/160543
75k (1v) 0.04 https://www.digikey.com/product-det...ronics-inc/CF14JT75K0/CF14JT75K0CT-ND/1830396
30k (1.15v) 0.04 https://www.digikey.com/product-det...ronics-inc/CF14JT30K0/CF14JT30K0CT-ND/1830386
2k (3.3v) 0.04 https://www.digikey.com/product-det...ronics-inc/CF14JT2K00/CF14JT2K00CT-ND/1830357

 

[Ikeprodigy]

These are the resistors I use. I prefer to get them from digikey but ebay or other online sources are fine too.

3x PTH08080 23.03 https://www.digikey.com/product-detail/en/texas-instruments/PTH08080WAH/296-20432-ND/724048
6x 100uf Cap 0.75 https://www.digikey.com/product-det...tronic-components/ECE-A1AKS101/P963-ND/160543
75k (1v) 0.04 https://www.digikey.com/product-det...ronics-inc/CF14JT75K0/CF14JT75K0CT-ND/1830396
30k (1.15v) 0.04 https://www.digikey.com/product-det...ronics-inc/CF14JT30K0/CF14JT30K0CT-ND/1830386
2k (3.3v) 0.04 https://www.digikey.com/product-det...ronics-inc/CF14JT2K00/CF14JT2K00CT-ND/1830357

Thanks! This helps a whole lot! What about for 5v?

 

[Gman]

Thanks! This helps a whole lot! What about for 5v?

I will teach you

1. Go to digikey.com

2. Type in "Resistor"

3. Check off search criteria example: 1/4watt, through hole, and resistance

4. Choose correct resistor that has stock available and a minimum quantity of 1. I recommend getting 10 resistors (or more) at a time, the price per quantity is lower generally.

If the actual resistance you are looking for is not available, choose a resistor that is closest and reference with pth08080 datasheet that the output voltage will be in range. Hint: 353 ohms is not available but 330 is pretty common http://www.digikey.com/product-deta...ronics-inc/CF14JT330R/CF14JT330RCT-ND/1830338

 

[ShockSlayer]

I use eBay. You won't be able to get the exact resistance, but you can get pretty close. You just have to search for more common values.

Recently ordered these:
86.6k http://www.ebay.com/itm/361896122596
34k http://www.ebay.com/itm/400014615433
1.8k http://www.ebay.com/itm/401125881849

For 5v I use AMS1117-5 regulators; the -5 means it's the fixed 5v version. It puts out about 1A, so it's plenty for most flash drives, just don't try to run an HDD with one.

 

[Ikeprodigy]

I will teach you

1. Go to digikey.com

2. Type in "Resistor"

3. Check off search criteria example: 1/4watt, through hole, and resistance

4. Choose correct resistor that has stock available and a minimum quantity of 1. I recommend getting 10 resistors (or more) at a time, the price per quantity is lower generally.

If the actual resistance you are looking for is not available, choose a resistor that is closest and reference with pth08080 datasheet that the output voltage will be in range. Hint: 353 ohms is not available but 330 is pretty common http://www.digikey.com/product-deta...ronics-inc/CF14JT330R/CF14JT330RCT-ND/1830338

Thank you so much Gman! This is very valuable information!

 

[Ikeprodigy]

I use eBay. You won't be able to get the exact resistance, but you can get pretty close. You just have to search for more common values.

Recently ordered these:
86.6k http://www.ebay.com/itm/361896122596
34k http://www.ebay.com/itm/400014615433
1.8k http://www.ebay.com/itm/401125881849

For 5v I use AMS1117-5 regulators; the -5 means it's the fixed 5v version. It puts out about 1A, so it's plenty for most flash drives, just don't try to run an HDD with one.

Great response! Thanks a ton!

 

[Fiskers1208]

thanks for making this thread. I really needed it. @ShockSlayer @
Gman is this for 7.4v batteries or for 14.8v

 

[Gman]

thanks for making this thread. I really needed it. @ShockSlayer @
Gman is this for 7.4v batteries or for 14.8v

It doesn't matter too much. The PTH08080 can operate between 4.5v and 18v. Although I would recommend using a 7.4v pack. http://www.ti.com/lit/ds/symlink/pth08080w.pdf

 

[Fiskers1208]

It doesn't matter too much. The PTH08080 can operate between 4.5v and 18v. Although I would recommend using a 7.4v pack. http://www.ti.com/lit/ds/symlink/pth08080w.pdf

okay but will there be a difference between the output

 

[GC64]

okay but will there be a difference between the output

No, as long as it is between 4.5v and 18v it will have the same output based on your resistor. Though you should make sure the voltage listed on your capacitor is at least double your input voltage.

 

[Fiskers1208]

No, as long as it is between 4.5v and 18v it will have the same output based on your resistor. Though you should make sure the voltage listed on your capacitor is at least double your input voltage.

so should I use this one

https://www.radioshack.com/products...ic-capacitor?gclid=CI2Xn7WKudICFYyLswodBRoHYQ

 

[Gman]

so should I use this one

https://www.radioshack.com/products...ic-capacitor?gclid=CI2Xn7WKudICFYyLswodBRoHYQ

The datasheet recommends 100uf.. not 1000uf.

 

[Ikeprodigy]

so should I use this one

https://www.radioshack.com/products...ic-capacitor?gclid=CI2Xn7WKudICFYyLswodBRoHYQ

Refer to the diagram that I upload from the custom regulator thread and the links Gman provided in this thread...

 

[Fiskers1208]

The datasheet recommends 100uf.. not 1000uf.

is this good

https://www.radioshack.com/products/radioshack-100uf-50v-20-radial-lead-electrolytic-capacitor

 

[Gman]

is this good

https://www.radioshack.com/products/radioshack-100uf-50v-20-radial-lead-electrolytic-capacitor

What do you think?

 

[Fiskers1208]

What do you think?

gc64 said "No, as long as it is between 4.5v and 18v it will have the same output based on your resistor. Though you should make sure the voltage listed on your capacitor is at least double your input voltage"

 

[Ikeprodigy]

gc64 said "No, as long as it is between 4.5v and 18v it will have the same output based on your resistor. Though you should make sure the voltage listed on your capacitor is at least double your input voltage"

Omg. Yes, it's good...

2*14.8= 29.6 and 29.6<50

 

[GC64]

gc64 said "No, as long as it is between 4.5v and 18v it will have the same output based on your resistor. Though you should make sure the voltage listed on your capacitor is at least double your input voltage"

that is true, I did say that.

 

[Fiskers1208]

Omg. Yes, it's good...

2*14.8= 29.6 and 29.6<50

that is true, I did say that.

The datasheet recommends 100uf.. not 1000uf.

thank you very much