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7805A is one of the linear regulator ICs that output accurate constant voltage, it can output constant voltage of 5V even if the input voltage is unstable. This IC is used to minimize the effects from input voltage fluctuations and is widely used in electronic circuits that require a constant voltage of 5V.
The 7805A is housed in a TO-220 package and allows the use of external components such as cooling fins for heat dissipation. This IC is used in a wide range of applications such as audio equipment, power supply units, instrumentation, and automotive electronics.
Besides the 7805A, there are also different output voltage versions such as the 7806A, 7809A and 7812A. These can output constant voltages of 6V, 9V and 12V respectively. In addition to the linear type, there are also switching types of constant voltage regulator ICs, which are used to design high-efficiency power supply circuits.