A voltage regulator (VR) is an electronic or electrical component used to create and maintain a fixed o/p voltage when the input voltage (or) load condition changes. These components play a crucial role in regulating & stabilizing electrical voltage levels. Voltage regulators maintain the voltages from a power supply that is well-suited to the other components. These are most frequently used for AC/DC power conversion, DC/DC & AC/AC power conversion. These devices are also used in electronic equipment where extreme differences in voltage would be harmful. This article provides brief information on the LM7809 voltage regulator, functionality, key specifications & its applications.
What is the LM7809 Voltage Regulator?
LM7809 IC is a fixed positive voltage regulator that is mainly designed to be used in a wide range of power supply applications. This voltage regulator IC offers fixed 9V output by 1A to 1.5A. In 7809 IC, the number “78” indicates a positive voltage regulator whereas 09 indicates the output voltage it provides like 9V. To get a stable & fixed o/p voltage of 9V & 1.5 amperes, the input voltage of this IC must be 11V & 2 amperes. So LM7809 IC is a very popular linear voltage regulator to generates fixed 9V output. If the input voltage of this IC is below 11V then this regulator IC will not generate a fixed 9V because it needs 2V over its actual o/p voltage to provide a fixed output.
This voltage regulator IC has in-built features like short circuit protection & overheat shutdown so this IC is reliable to use in various educational projects & commercial applications. This IC is simple to use with no external components or circuitry except a few smoothing capacitors for voltage regulation. This IC uses a heatsink because all the voltage differences will change into heat within the regulator IC.
The pin configuration of LM7809 IC includes the following.
- Pin1 (IN): It is a positive voltage pin which is an input to this pin.
- Pin2 (GND): It is a ground pin that is very common to both input & output.
- Pin3 (OUT): It is an output pin that provides 9V output.
Features & Specifications:
The features and specifications of the LM7809 voltage regulator IC include the following.
- It is a three-terminal LM series voltage regulator IC.
- This IC is available in TO-220, KTE & TO-3 packages.
- The output current of this IC ranges from 1A to 1.5A.
- This IC provides a fixed & stable output voltage like 9V.
- The max input voltage of this IC is 35V DC.
- The sleep mode (or) standby current consumption is 8mA only.
- The input voltage of this IC minimum is 11V.
- The maximum input voltage of this IC is 35V.
- Its PSRR or ripple rejection is 55 dB.
- This IC has thermal overload & short circuit current limiting protection internally.
- Its maximum junction temperature is 125 degrees Celsius.
- Its nominal supply current is 5mA.
- Its quiescent current is 8mA.
- Its maximum voltage dropout typically is 2V @ 1A.
- Its MSL or Moisture Sensitivity Level is 1 (Unlimited).
- The technology used is BIPOLAR.
- The type of output is fixed.
- Its accuracy is 4 %
- Its maximum voltage tolerance is 4.4%.
Equivalent & Replacements
Equivalent L7809 voltage regulators are; LM7824, LM7806, LM7815, LM317, LM7905, LM7812, LM7912, LM7809, UA7809, L7809 and KA7809. Replacement of L7809 voltage regulators are; LM340T9, LM2940CT-9.0, and LM340AT9.0.
How to use L7809 IC Very Safely in a Circuit?
To get reliable & long-term performance of L7809 IC very securely in a circuit it is suggested not to provide > 35V to this regulator IC. You should not drive any load > 1.5A and use an appropriate heatsink with this IC always. This IC must operate > temperature 0 degrees centigrade & < +125 centigrade. The storage temperature of this IC must range from -65 to +150 degrees centigrade.
9V Power Supply Circuit with LM7809 IC
Every electronic device has a power supply circuit that changes AC to DC supply. So here we are going to design a 9V DC power supply circuit with an LM7809 voltage regulator IC. LM7809 IC is a significant component in a 9Volts power supply circuit where this IC restricts the output voltage to 9Volts & draws a 9V regulated power supply. This is the most commonly used IC because its regulated 9V voltage supply gives a very convenient power source mainly for most TTL components. The 9V power supply circuit with LM7809 IC is shown below.
The required components to make this power supply circuit mainly include; a Breadboard, LM7809 IC, 230V to 16V 2A 50Hz step-down transformer, 2A bridge rectifier diode, 470μF 50V electrolytic capacitors, 0.01μF ceramic capacitors and connecting wires. Connect this circuit as per the power supply circuit diagram shown below.
In this circuit, first, a power transformer is used at the input of a DC power supply. After this, a bridge rectifier is used to change DC to AC which supplies throughout a smoothing filter. After that, it goes through a voltage regulator IC with some capacitors to eliminate any ripples or noise.
First, 230V of an input voltage is applied at the transformer’s primary winding that steps down 230V to 16V 2A through mutual induction of two windings while maintaining 50Hz frequency. After that, a 16V AC signal is supplied throughout a bridge rectifier to change the signal from AC to DC signal. After that, this DC signal supplies through C1 and C2 smoothing capacitors before passing on to an LM7809 IC. This voltage regulator IC generates a fixed 9V DC signal at the output. After that, this output DC signal is supplied throughout the C3 capacitor to eliminate any noise before generating the output.
Generally, DC power supplies are used widely in low-voltage applications like; automotive applications, aircraft applications, charging batteries, and other low voltage & current-based applications.
The advantages of the LM7809 voltage regulator include the following.
- It is a fixed, self-contained linear voltage regulator.
- LM7809 IC is very simple to use without any external circuit.
- This voltage regulator provides approximately 500 mA of current without any heatsink.
- This IC does not need any component to saturate or balance its o/p voltage.
- This IC has inbuilt protection to protect from short-circuit & overheating.
- These are available at low cost and in different surface mount packages.
- These ICs are efficient and reliable.
- It has a wide input and high output range.
- It has a robust construction.
The disadvantages of the LM7809 voltage regulator include the following.
- LM7809 voltage regulator dissipates more heat.
- When the difference between the i/p voltage & o/p voltage is large then the loss will be large.
- Step-down operations are possible only.
LM7809 Voltage Regulator Applications
The applications of the L7809 voltage regulator IC include the following.
- L7809 voltage regulator IC is used for step down of voltage.
- These are used in power supplies, solar supplies, battery chargers, motor drivers, and microcontroller power supplies.
- These are used to provide stable +9V output voltage to power sensors & microcontrollers in most of the electronic projects.
- These are used in regulated dual supply, used as adjustable o/p regulators, current limiters, and o/p polarity reversal protection circuits.
- These voltage regulator ICs are used in audio equipment.
- These ICs are used in automotive systems like sensors, lighting controls & ECUs.
- L7809 voltage regulatocgfww r IC is used in battery charging circuits for maintaining a stable voltage in the charging process.
- These regulator ICs are used in DIY projects.
Please refer to this link for LM7809 Voltage Regulator Datasheet.
Thus, this is an overview of the 7809 voltage regulator IC, pin configuration, specifications, circuit, working, and its applications. This regulator IC is a versatile chip that is widely used for providing a fixed +9V output voltage. Its functionality, specifications, and applications will make this IC a significant part of various electronic systems which range from power supply units to automotive & DIY projects. Here is a question for you, what is LM330 IC?