Small UPS Circuit for Router Backup

Never lose connection again, make this Small UPS Circuit for Router Backup.

When there is power cut then internet goes off.

Router and modem stop.

Small UPS solve problem.

This give backup to DSL modem and WiFi router.

This circuit is with simple parts, easy to build and with low cost.

Circuit Working:

Parts List:

The above circuit diagram can power DSL or WiFi routers.

It can also run any device that works on 9V or 10V.

Input supply 15V to 32V DC.

IC LM338T work as adjustable regulator.

Output voltage set by R1 and R2.

Capacitor C1 filter noise at input.

Capacitor C2 smooth output.

Diodes D1 to D3 give isolation and drop voltage.

One output goes to 12V battery charging.

Another output goes to router or modem 9V to 10V.

Battery give backup when main power fail.

Formulas:

Formulas for Small UPS Circuit for Router Backup is shown below:

Output voltage Vout = 1.25 * (1 + R2/R1)

here.

• Vout​ is the output voltage of the LM317
• 1.25 V is the reference voltage of LM317
• R1 is the resistor between Adj pin and ground
• R2 is the resistor between Vout and Adj pin

How to Build:

To build a Small UPS Circuit for Router Backup follow the below steps:

• Gather all the parts as shown in circuit diagram.
• LM338T pin1 Adj connect to R1 and R2.
• Pin2 Input connect to DC supply + through C1.
• Pin3 Output connect to R2, capacitor C2, D1 To D3 diodes chain.
• Battery connect at output between diodes D1 and D2.
• Router connect at end after diodes.
• Negative line is common ground.

Conclusion:

This Small UPS Circuit for Router Backup is small and useful.

It keep modem and router alive in power cut.

It is build simple with few parts.

No need of big inverter.

Internet stays ON, even when electricity is gone.

References:

How can I make (DIY) a UPS on my own to support a WiFi router functioning during power outages?