L7812CV Voltage Regulator: Internal Structure, Characteristics, Specifications and Other Details
01 February 2024
L7812CV is a linear voltage regulator, which is a common integrated circuit used to stabilize and adjust the power supply voltage to ensure that the connected circuit operates at a stable voltage. In this article, we will provide information about this linear regulator, including the internal structure and operating principle, features and applications, with pinout diagrams.
The L7812CV is an integrated circuit also known as a voltage regulator. It is a linear voltage regulator with a fixed positive 12 volt output. It reduces the input voltage to a stable 12 volt output voltage. L7812CV is commonly used in electronic equipment that requires stable voltage. For example, it can be used in various digital and analog circuits on printed circuit boards (PCBs), power amplifiers, DC motor drivers, etc. This voltage regulator ensures that these circuits operate normally without drastic changes in supply voltage conditions.
The L7812CV has some advantages over other types of voltage regulators. For example, its output voltage is very stable and highly precise, and can provide stable power to various electronic devices. In addition, it has a protective function that prevents the circuit from damage such as overcurrent or overheating.
Alternatives and equivalents:
L7812CV is made using polysilicon manufacturing process and mainly includes four parts: voltage regulator, power transistor, overload protection circuit and thermal protection circuit. When the input voltage is higher than the set value of 12V, L7812CV adjusts the voltage through the power transistor to stabilize the output voltage at 12V. When the output current exceeds the rated value, the overload protection circuit automatically cuts off the output. When the chip temperature exceeds the reliable operating range, the thermal protection circuit will automatically cut off the circuit to avoid overheating damage.
The functions of each pin of the three-terminal voltage regulator L7812CV are shown in the figure above. Among them, pin 1 is the input of the voltage regulator, pin 2 is the ground terminal of the voltage regulator, and pin 3 is the output of the voltage regulator.
A three-terminal voltage regulator is a semiconductor device that has a very high resistance until the critical reverse breakdown voltage. When the voltage regulator tube undergoes reverse breakdown, it can maintain the terminal voltage almost unchanged within a certain current range (or within a certain power loss range), showing significant voltage stabilization characteristics. Therefore, it is widely used in regulated power supplies and limiting circuits.
• Package types: This regulator is available in a variety of package options to accommodate different design layouts and manufacturing requirements.
• Protection functions: L7812CV may have protection functions such as overheating protection to prevent the chip from being damaged.
• Current capability: This regulator is usually available in different versions with different maximum output current capabilities.
• Input and output voltage range: This voltage regulator usually needs to operate within a certain input voltage range, while the output voltage will remain stable.
• Voltage stabilization function: This voltage regulator is capable of regulating the input voltage to a fixed output voltage. In this case, the 7812 indicates that its output voltage is 12V. Therefore, it is widely used in circuits that require stable 12V voltage supply.
• Linear regulation: It is a linear regulator, which means it regulates the output voltage by converting excess input voltage into heat. Therefore, the L7812CV is suitable for lower power applications. For high power needs, it may not be as efficient as a switching regulator.
The best and most reliable way to judge the quality of the L7812CV is to power it up and measure its output voltage. The specific steps are as follows: We will face the side with the words towards ourselves, with the pins facing downwards. From left to right, they are pin 1, pin 2 and pin 3. We prepare a DC power supply with a voltage range between 15V to 25V. We connect the positive pole of the power supply to pin 1 of the L7812CV, and the negative pole to pin 2 of the L7812CV (or the heat sink is also acceptable). Then we use a multimeter to measure the voltage between pin 3 and pin 2. The normal value should be about 12V. If the output voltage is normal and the L7812CV has no obvious temperature rise, it means that the L7812CV is good.
• Motor control: In some motor control circuits, a stable voltage is needed to supply the control circuit and drive the motor. The L7812CV can provide a stable 12V voltage in these cases.
• Electronic experiment board: The L7812CV is an electronic experiment board with good voltage stabilization performance, which can be used to build various electronic experiments. With excellent voltage regulation performance, this experiment board can provide a stable 12 volt power supply for experiments. Whether you are making basic electronic measurements, designing circuits, or investigating the workings of complex systems, the L7812CV can provide reliable power support for your experiments.
• Automotive electronic system: In the automotive electronic system, L7812CV is a very practical power management IC, which can be used to provide a stable power supply so as to provide a stable working environment for all kinds of electronic devices in the car. This stable power supply ensures that the car audio system can play clear, noise-free music, the central processor can accurately and quickly process various commands, and the sensors can accurately monitor the working status of the car, etc.
• Power adapter: In applications that require +12V, we can ensure that the output voltage of the power adapter is stabilized at +12V by using the L7812CV. Specifically, we connect the output of the power adapter to the input of the L7812CV, and then connect the output of the L7812CV to the device that requires +12V voltage. By doing so, the L7812CV can effectively adjust and stabilize the output voltage of the power adapter at +12V.
• LED lighting system: This regulator is capable of stabilizing the input voltage at +12V and outputting a stable current, making it ideal for use in LED lighting systems. By connecting the output of the L7812CV to the power supply of an LED bead or LED fixture, it can provide a stable power supply for the LEDs to work properly and maintain consistent brightness and color.
• Amplifier and analog circuits: In addition to electronic devices, the L7812CV is widely used in amplifiers and analog circuits. A stable power supply is needed in audio amplifiers to ensure the accuracy and clarity of audio signals. Using the L7812CV ensures that the amplifier's operating voltage is stabilized, thus improving the quality and clarity of audio. In analog circuits, the L7812CV can also provide a stable power supply for the circuit to ensure the accuracy and stability of analog signal processing and transmission.
When using L7812CV, we need to pay attention to the following points:
1. Short-circuit protection: L7812CV has short circuit protection function. But it should be noted that under short circuit conditions, the voltage regulator will generate a lot of heat, so we should try to avoid short circuit conditions.
2. Filter capacitors: Filter capacitors should be selected to ensure the stability of the input voltage and the performance of the regulator. Usually, the capacitance of the filter capacitor should be between 0.1μF and 1μF.
3. Output capacitance: The output capacitance should be selected to ensure the stability of the output voltage and the performance of the regulator. Typically, the output capacitor's capacitance should fall within the range of 1μF to 10μF.
4. Heat dissipation: L7812CV will generate a certain amount of heat during the working process, so we need to take appropriate heat dissipation measures. Usually, we can install a heat sink on the regulator or place the regulator on a heat sink.
5. Input voltage: The input voltage should be within plus or minus 5 percent of the nominal value, otherwise it may affect the output voltage. In addition, the input voltage should be within the operating range of the voltage regulator, otherwise it may cause damage to the regulator.
Frequently Asked Questions
1. What is L7812CV?
The L7812CV is a three-terminal positive voltage regulator. This regulator can provide local on-card regulation, eliminating the distribution problems associated with single point regulation.
2. What is LM7812 voltage regulator?
LM7812 is a positive voltage regulator that outputs +12 volts. The LM7812 is a three-pin IC. Output Current up to 1.5A.
3. What is the L7812CV used for?
It's perfect for use in electronics projects and practices. You can integrate it into a breadboard such as a breadboard, PCB, phenolic board and have an ideal replacement if your voltage regulator breaks.
4. What is the spec of L7812?
The L7812 is a 3-pin voltage regulator that converts an input voltage ranging from 14V to 35V into a constant 12V output, capable of delivering up to 750mA. These voltage regulators are ideal for a wide array of applications.