Simple UPS

Description.

This is the circuit diagram of a simple UPS that can deliver 12V unregulated and 5V regulated DC. The transformer T1 steps down the mains voltage to 12V AC and then the bridge B1 rectifies it. The rectified signal is smoothed by the capacitor C1.When the mains supply is available the battery will be charged via diode D3 and the regulator IC gets supply via diode D5. 12V and 5V DC will be available at the output terminals. When mains supply is not available the battery supplies current to the regulator IC and to the 12V DC terminal through diode D4.Also, the diode D3 blocks reverse flow of current during battery mode. Capacitors C2 and C3 acts as filters.

Circuit diagram with Parts list.

simple-ups-circuit

Notes.

  • Assemble the circuit on a good quality PCB.
  • The transformer T1 can be a 230V AC primary, 12V secondary,3A step-down transformer.
  • The bridge B1 can be a 2A bridge. If such a bridge is not available, make one using four 1N4007 diodes.
  • The capacitor C1 must be rated at least 25V.
Custom Search

Leave a Reply

51 Responses to “Simple UPS”

  • maher waheed ahmad says:

    sir how this circuit invert 12 v in to 230 v ?

    • Seetharaman says:

      Hi this is a circuit supply 12 and 5 volt dc from 230 volt AC. in the event 230 ac fails the inbuilt battery will supply 12 and 5 volt dc supply to the load.

  • maher waheed ahmad says:

    up ur knowledge

  • fabio says:

    hi sir
    which kind of battery can connect?

  • T.ASAITHAMBI says:

    Sir,can i use 12-0-12 center tapped transformer instead of 12-0 for simple ups system

  • husni says:

    I think 5v and 12v out is in dc,and only dc load can be connected.hw it can be connected to a ac load.

  • rajib ranjan says:

    how does work transistor?

  • ganpat says:

    sir i need the rating for batterty use for above simple ups and which type of load are connected to this ups.and provide complet working of this ups .

  • this circuit cannot charge 12 volt battery. in operation the battery dicharges continuosly when the circuit is connected to the main power source.

  • cooool says:

    Hi sir what change is required for 6v 8.5amp battery?

  • cooool says:

    Sir what is change required for 6v 4.5amp battery.please reply me

  • cooool says:

    seetharaman sir what is change required for 6v 4.5amp battery

  • cooool says:

    Sir what change is required for 6v 4.5 amp battery

  • cooool says:

    Thankyou seseetharaman sir.

  • cooool says:

    Hi seetharaman thankyou for reply. what is the suitable transformer for the battery 6v 4.5amp and 6v 8.5amp connected in series.

    • Seetharaman says:

      Hi coool you cannot connect two batteries of different AH rating in series for while charging them, they will loose their operating life expectancy as their charge characteristics are different.

  • cooool says:

    Sir this circuit has facility of over charge protection? Please reply me

    • Seetharaman says:

      Hi cooool the transformer is suitably chosen to take care of it. the max charge current is taken care by R1.

  • akuure felix says:

    sir, please i need more explanation to build this circuit sir,
    i want to know how the inverter change the 12v to the 220v cos i can not see the step up transformer in the circuit and more so the inverter circuit is not clear to me.

  • ahmad fadaei says:

    Hello.
    I’ve made the circuit., But the output voltage is 16 volts, why?

    Urgent Please…

  • ram raj says:

    sir I want simple ups circuit diagram please replay me

  • arun prasanth.k says:

    for what purpose the resistance R1 (220ohms) used in this circuit?
    pls reply sir..urgent we are moving with this mini project….

  • vasanth says:

    can we use this ups circuit to power the computers……. what is unregulated 12 v supply please reply me soon

  • divya says:

    the circuit is super.it is so easy to understand.thankyou.

  • Andrew says:

    ok, this circuit will charge the battery?

  • sohail says:

    plz sir reply me through email address

  • sohail says:

    sir i want to see the battery bank circuitry inside the ups and how we can estimate the ups health and this is possible to estimate batteries health individually or we can estimate the health of the banks as a whole.

  • Aby says:

    Dear all

    we are looking 96/120V on line ups charger

  • Ganesh R says:

    Respected sir,
    thanks for quick reply.. I need a circuit of 16v unregulated and 12v regulated with atleast 1.2A as output.. I’m planning to use 16-0 3A step down transformer.. So i’m planning to use 7812 IC instead of 7805 ic inside the circuit to get 12v 1.2A as the output.. My questions are
    1) Will the ic 7812 work fine and give 12v and 1.2A as o/p?
    2) wat resistor should i use to charge the battery, 4.4 ohm 10w or more?Is there any over charge protection step for the battery?
    3) And is 3A transformer enough for charging battery and to power my dlink internet modem of 1.2A at the “same time”?
    4)Also i want to add a battery over charging protector circuit as in http://www.circuitstoday.com/automatic-led-emergency-light . its for 6v battery. i want to use it for my 12v battery with 16v transformer o/p.. just tell me what all to be changed..

    Plz kindly answer all the 4 questions.. Plz sir, i’m in very confused situation.. I know i’m torturing you, even though i’m thanking you for your valuable support.. Thanks will u plz reply via email ganeshrnet{@}live{.}com

  • Ganesh R says:

    Respected sir,
    thanks for quick reply.. I need a circuit of 16v unregulated and 12v regulated with atleast 1.2A as output.. I’m planning to use 16-0 3A step down transformer.. So i’m planning to use 7812 IC instead of 7805 ic inside the circuit to get 12v 1.2A as the output.. My questions are
    1) Will the ic 7812 work fine and give 12v and 1.2A as o/p?
    2) wat resistor should i use to charge the battery, 4.4 ohm 10w or more?Is there any over charge protection step for the battery?
    3) And is 3A transformer enough for charging battery and to power my dlink internet modem of 1.2A at the “same time”?
    Plz plz plz kindly answer all the 3 questions.. Plz sir, i’m in very confused situation.. Thanks will u plz reply via email ganeshrnet{@}live{.}com

  • seetharaman says:

    Hi Ganesh R1 should be 2.2 ohms 10 watts wire wound resistance. If you donot include the battery may get damaged over a period of time.

  • Ganesh R says:

    Sir, i wish to know whether the removal of R1 which is 220ohms for better charging of the 12v battery? I think the battery when connected in serial with a resistor will reduce the charging efficiency? So if we can remove and adjust the resistor, it will be better no? Is there any problem in that? Will it affect auto charging or will it reduce the output voltage to the unregulated 12v lead, while in power mode condition? And also I’ve designed my own circuit diagram removing R1 220ohm.. the link to the described diagram is : http://i43.tinypic.com/flx106.jpg please see it and reply via email ganeshrnet{@}live[.]com

  • seetharaman says:

    Hi Sooraj if you are using 12volt 7AH battery and if you load is around 1.5amp both 12 and 5 volt put together then it will work for 4hrs during a power breakdown.

  • sooraj says:

    plz tell me about its backup time and price for creating one. i mean overall price including the battery..

  • seetharaman says:

    Hi Abdullah what are your plans with this circuit. what is your application.

  • abdullah says:

    Can we increase batteries in this circuits…….!

  • ruban says:

    what about cost and output supply

  • Seetharaman says:

    Hi Electrominds the transformer itself is rated for 12 volts hence with the pk voltage of 16.8 volt in series with R1 220 ohms, the drop across D3 and power consumed by LED, put together will not over charge the battery will only trickle.
    to charge drained battery the resistance R1 has to be reduced to 6.8 ohms 10watt. with fully charged battery 0f 7AH 100mA will be trickling the battery.

  • electrominds says:

    is there any overcharging protection in the circuit

  • max says:

    hi, can i have the component list for this circuit

  • seetharaman says:

    Hi Edgardo You use 24 volt battery increase transformer rating to 24volt 2Amp secondary rating. use a standard adjustable regulator before F2 for whatever voltage you want. you may use one of the regulator circuit published in Circuits today. If your current requirement is within 1amp you can use LM317T ic voltage regulator. you can refer to manufacturers data sheet
    http://www.national.com/ds/LM/LM117.pdf

  • EDGARDO DIOLOLA says:

    This a good circuit.
    Can I have a circuit diagram same as this having voltage output of still 5V, but the other output is 19VDC, of course, the battery will be 24 Vdc.I just do not know how to design a circuit to have an output of 19VDC, 5VDC.
    More power to you.

  • Niranjan k.c says:

    It is very very good website I like it and you also visit my site and give me some ideas for it betterments.

  • Solomon Igwe says:

    I need an overload protector circuit for an inverter circuit of 3KVA