Basic UPS Circuit 5V and 12V DC

electronic circuit diagram

The above diagram is a basic Uninterupted Power Supply (UPS) circuit. This basic UPS circuit is a very simple and inexpensive.

This circuit can be adapted/modified for other regulated and unregulated voltages by using different regulators and batteries. For a 15 Volt regulated supply, you may apply two 12V batteries connected in series (it will become 24V) including a 7815 regulator (will be 15V stabilized voltage output). There is a lot of flexibility in this circuit.

TR1 has a primary matched to the local electrical supply which is 240V in the UK (it might be various for other countries, 110/120V or 220/240V). The secondary winding should be rated at least 12 Volts at 2 Amperes, but can be higher, for example 15 Volts. FS1 is a slow blow type and protects against short circuits on the output, or indeed a faulty cell in a rechargeable battery. LED 1 will light ONLY when the electricity supply is present, with a power failure the LED will go out and output voltage is supplied by the battery.

The capacity to keep up the regulated supply with no electrical supply relies on the load taken from the UPS and also the Ampere hour capacity of the battery. In the event that you were utilizing a 7A/h 12V battery and load from the 5V regulator was 0.5 Amp (and no load from the unregulated supply) then the regulated supply would be maintained for around 14 hours. Greater A/h capacity batterieswould give a more drawn out standby time, and the other way around.

The complete explanation about this basic UPS circuit, please go to this page.

68 thoughts on “Basic UPS Circuit 5V and 12V DC

  1. dear sir,i am an electrical engineer of sunyani polytechnic,i need a circuit diagram of ups of two batteries of which one can take over after the first battery has completely discharged. pls i am using it for my project work.

  2. i’d be very much pleased if could send me a circuit diagram for 2kva ups of 12v battery combinations.thank you.

  3. how could i use a circuit like such to be a dumb DC-DC UPS, effectively a source switch, where it only switches to battery when the primary input either fails or falls below a certain wattage, e.g. 90W

  4. Hi, I am a student of EEE, My project is UPS. Anybody pls help me by giving a full ups circuit. I will be very grateful to him.

  5. i am a engineering student and i want to complete my project. kindly send me a simple and unexpensive ups circuit diagrame

  6. i need a circuit diagram of a ups that uses two 12v/9amps batteries.what may be the problem that a ups will not supply when remove from main power source or when there is power outbreak.

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