5 VDC 3 Amp Linear Power Supply for Router - W1AEX

The little 5 VDC 2.5 amp switching supply that powered my D-Link DGL-4300 router has been spewing obnoxious roaming oscillations up and down the 160 meter and 75 meter bands. After attempts to shield and bypass the power supply failed, I tried a few pounds of ferrite cores, which also failed miserably. So, I ravaged my junk box and built a strapping 5 VDC linear regulated supply. As expected, it is RF silent, and easily handles its power supply duties for the router. In the background, you can hear Rich, K1ETP and Joe, WA1IWQ running AM on 1.885 Mhz with no more buzzy, raspy, switching power supply noises. Silence is golden.

There's nothing special about the design of the supply, which is based upon the NTE 931 5 volt 3 amp linear regulator device in a T-03 package. The case was from an old discarded HP VTVM which worked out nicely because the meter could be wired in to display the 5 VDC output. All the other parts were ripped out of my junk pile. The total cost of the project was less than 20 bucks, with the majority of that from the cost of the NTE 931 which was purchased new for 12 dollars. The same thing could be accomplished with a much cheaper 7805 regulator, but a pass transistor such as a 2N3055 would have to be added in to handle current demands greater than 1 amp. I wanted to keep it simple, so I went with the least complex solution. The schematic for the basic regulator is available at the link below:

http://members.cox.net/ender/DGL-4300-5VDC-Regulated-Sup.jpg

Category:

Science & Technology

Tags:

• ham radio
• W1AEX
• NTE-931
• WA1IWQ
• K1ETP
• 160 meter AM

[meade9166]

is the 2n 3055 a voltage regulator?please answer

[ender06026]

@meade9166 Alex has it right. The 2N3055 can be used as a pass transistor to carry heavier current at a regulated voltage that using a simple 7805 regulator. I liked using the NTE 931 heavy current regulator just to keep it simple.

[ronwoch]

Cool! I found this video trying to look up the HP voltmeter I got, that appears to be the same or similar to the case that you used for this. (HP 400H)

[Alex1M6]

@meade9166 The 2n3055 is an NPN transistor.