Small UPS circuit diagram, 6V-7V backup

This small emergency backup battery systems as Simple ups circuit diagram, can be applied to many applications, when the power goes, the battery can provide backup power automatically. This power supply circuit system consists of a transformer, a bridge rectifier and an electrolytic capacitor. And there is a zener diode for controller the output power transistor(BD135 NPN) of this circuit, and will be determined at a constant voltage of 7.5 volt.

The Backup battery 7.5V(1.5Vx5) in series with D2 and both are connected to across the output terminal. Voltage drop across D2 serves to reduce the voltage level of the power supply down to about 7V. When the light from the fire house, R2 serves to charging the dry batteries or the battery power is accumulated in the circuit, to prevent over-charging R2 will take control. By simply keep the current flowing from the battery runs out while using the full functionality of the home. Resistance that can be calculated. By dividing the voltage between the zener diode and battery, with value battery voltage for safety.


The detail parts
BD135________NPN transistor
R1,R2________ 1K____1/2W Resistors
C1___________1,000 microfarad 25 volt___electrolytic types.
C2___________100 microfarad 25 volt____ electrolytic types.
ZD1__________ Zener diode 8.2 volt 0.5 watt
D1___________ The Diode 1N4001 (50 volt 1amp)
T1___________ Transformer 500mA 10V
B1___________ AA battery 1.5V x 5 pcs

How to builds.

We use the equipment a very small, so it is not necessary to make printed circuit boards. We can all soldering electronics (except for transformer) on the prototype board small size. Choose a charger for the battery size AA 1.5Vx5 = 7.5V or size 6 volt lead-acid battery, it works great as well. This circuit can supply enough current to 500mA circuit applications, such as small digital clock. Small emergency lighting system and more.

6V backup battery power supply regulator with IC 7805

This simple and cheap 6 volt power supply circuit with 6V backup battery system or 6V ups circuit diagram.

The AC power 220V is entered to through input of transformer-T1 to reduce voltage as 9VAC, then wire connected to four diode D1-D4 as bridge rectifier became to 11VDC, then the current is filtered to dc voltage that low ripple output and then the voltage is regulated to 6VDC constant voltage by IC-KA7805( IC-7805 type) In normal it is used for 5 volt only but now we add two resistor to determined output voltage is 6 volt and passed through diode 1N4002-D6 to output is 6 volt.

The current operate via the diode D1 and R3 to charge the 6 volt battery Ni-cad type.
When not have the electrical supply line, the current of battery are passed through D7 and S1 to output automatically.
The LED1 and R4-470ohm for display power on of this circuit.


Part list
IC1______LM7805,KA7805_____DC regulator 5 volt
C1_______2,200uF 25V_______Electrolytic Capacitors
C2_________33uF 25V______Electrolytic Capacitors
C3_______1,000uF 25V______Electrolytic Capacitors
D1-D7____1N4002____Diode 100V 1A
LED1_____LED any color as you like.
R1_______270 ohm 1/4W resistor
R2_______47 ohm 1/4W resistor
R3_______680 ohm 1/4W resistor
R4_______330 ohm 1/4W resistor
Sw1______on/off switch
T1_______Transformer____1A output 9V
F1_______Fuse 0.5A

Other circuits involved.

You can see the circuit about “regulator ic 7805? here : Regulator 5V,6V,9V,12V 1A By IC 7805,7806,7809,7812
And see more:

  1. backup battery systems circuit
  2. 6V power supply
  3. Basic Dual DC Power Supply 6V
  4. Change the output voltage of 7805 by diode.

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  1. Jonathan October 18, 2012
  2. excess October 19, 2012
  3. George Hanson Ofori August 3, 2014
  4. Ka September 25, 2014

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