October 18, 2021

Things You Should Know about IC LM 78XX Series for Power Supply Regulator

When you have electronic components that need to maintain a consistent voltage amount, you’ll need a voltage regulator to make that happen. A constant voltage level may be the only way to prevent the integrated circuit from overheating.

The voltage regulators of the LM 78XX Series are a more affordable and easier to use option for managing the power supply of your electronic circuits. The “XX” letters represent the voltage output amount of the integrated circuit. For instance, if the output is 5 volts, then it would be written as LM 7805. If the output is 15 volts, then it would be written as LM 7815.

The LM 78XX Series of voltage regulators are known for being positive voltage regulators. Do not confuse these with the 79XX Series of voltage regulators, which are negative voltage regulators. However, you can use the 78XX Series and 79XX Series together in order to give a positive voltage supply and negative voltage supply to the same electronic circuit.

Now let’s discuss some of the pros and cons of the LM 78XX Series.

Pros 

The LM 78XX Series gives you affordability and efficiency in the voltage regulators without requiring any extra components. You can regulate the power source consistently just fine without needing too much space. When you look at comparable voltage regulators on the market, they often need extra components for the output voltage level to be set properly. There are some types of voltage regulators that require you to have engineering skills. The switched-mode power supply is an example of this.

You’ll never need to worry about your LM 78XX Series circuits drawing excessive amounts of power because they have protection features built into them. Issues like short-circuiting and overheating are prevented by these protection features. This is a big reason why LM 78XX Series voltage regulators are used in so many applications. Even though the current is limited in devices of the LM 78XX Series, this limitation is protection for the circuits and the parts associated with them.

Cons

The input voltage is usually required to be at least 2 volts more than the output voltage. Because of this, the LM 78XX series voltage regulators may not be able to manage the power of certain devices. For example, if you’re using 6-volt batteries to power a 5-volt electronic circuit, then you cannot do this if you have an LM 7805 voltage regulator.

Since the input voltage must be more than the output voltage, all that additional input voltage turns into extra heat. Not only does this waste power which doesn’t get used, but it also means you need a good heatsink for certain applications. All that wasted power will lower the efficiency of the regulator in these circumstances. The higher the input voltage is than the output voltage, the more inefficiency that will be experienced.

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Conclusion

Overall, the LM78XX Series is an affordable and effective series of voltage regulators. If you can overcome the excessive voltage hurdle by trying to keep the input voltage as closely matched to the output voltage as possible, then you won’t need to worry about wasting too much power. It all depends on the batteries you purchase and the amount of voltage they have. For instance, if you choose 25-volt batteries for a 5-volt electronic circuit, then you’re going to waste 20 volts of power. But if you choose 7-volt batteries, then you’ll find them much more efficient.

The LM 78XX Series gives you safety and thermal overload protection without the need for external components. The voltage regulators come in an aluminum TO-3 package and have a current limit to the internal short circuit.

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