A backup battery or UPS gives power to an electronic appliance when the main electric power source is inaccessible. Similarly, this 9V battery backup circuit will function as a small normal UPS. This circuit will quickly rely on battery power if the input voltage is unavailable. Because of it, the appliance won’t face any restart. This circuit utilizes a 7809 IC to drop the voltage from 12 V to 9V. This 7809 IC is an independent fixed direct voltage regulator integrated circuit. Moreover, the IC belongs to a 78xx voltage regulator family which is generally utilized to regulate power supply in electronic circuits. The IC 7809 isn’t as well-known as 7805.
Hardware Components
The following components are required to make 9V Battery Backup Circuit
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1. | Voltage Regulator IC | LM7809 | 1 |
| 2. | Diode | 1N4002 | 1 |
| 3. | Battery | 12V | 1 |
| 4. | Capacitor | 330nF, 100nF | 1, 1 |
| 5. | Battery Charger | 12V | 1 |
| 6. | Battery Plug | 12V | 1 |
LM7809 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of LM7809
9V Battery Backup Circuit
Working Explanation
This circuit operates in such a way, that the LM7809 voltage regulator IC scaledown the 12V input voltage to 9V regulated output voltage. Additionally, a 12V lead-acid battery of any Amp Hour (AH) is utilized to power this circuit. The circuit will give output current up to 1 ampere. Furthermore, utilize a decent quality automatic 12V battery charger. Else, you can utilize a ready-made automatic 12V battery charger in this circuit.
Important note: Do not utilize under 3A battery charger with this circuit. Because it won’t charge the battery appropriately. Around 2A current will be required by the LM7809 IC itself.
Applications and Uses
- It utilizes to provide Emergency power to various electric appliances
- Helps in charging mobile phones, tablets, etc
- It can likewise utilize in emergency lighting, alarms, and CCTV cameras
