All the circuits discussed below require an unregulated input voltage max. Please note that the diagram may show LM which has identical features and specs as LM, thus both are interchangeable. The IC incorporates just two resistors, one is the fixed reference resistor R1 and the other one is a variable type for adjusting and receiving the desired voltage outputs. The maximum current here is limited up to 1.
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All the circuits discussed below require an unregulated input voltage max. Please note that the diagram may show LM which has identical features and specs as LM, thus both are interchangeable. The IC incorporates just two resistors, one is the fixed reference resistor R1 and the other one is a variable type for adjusting and receiving the desired voltage outputs.
The maximum current here is limited up to 1. The set up becomes ideally suitable for all small power supply applications, the IC being featured with complete over voltage, short circuit, over load and thermal run away protections is free from all voltage related hazards and thus becomes a favorite with new electronic enthusiasts. Adjustable Regulator with Improved Ripple Rejection The figure shows a standard LM wiring layout used for obtaining variable output voltages from 1.
However the inclusion of C1, C3 and D1 helps to improve ripple rejection greatly and enhances the overall regulation of the circuit. Slow Turn-On 15V Regulator In this configuration the voltage is fixed and clamped at 15 volts through appropriate selections of R1and R2. The inclusion of an extra transistor R3 and C1 makes it sure that the output of the circuit turns ON gradually after an input supply is applied. The output switch ON period will depend on the value of R3 and C1.
Increasing the values will produce higher time delays and vice versa. The feature ensures safe surge protected switch ON of the preceding electronic circuit, becomes ideally compatible with high power amplifiers where a slow turn ON of the speakers becomes very crucial for avoiding sudden dangerous voltage "pops" in the speakers during power switch ONs.
As the name suggests the function of the circuit is to act as a regulated buffer and reproduce exactly the same power which is being applied at the free end of R1. The output obtained from this circuit is overload and short circuit protected. The parts wired around LM helps to generate variable outputs featuring constant voltage and constant current levels at the respective adjusted values. Voltage is varied through R8 while R2 takes hold of the current adjustment operations.
The diodes are included for providing extra safety to the ICs. The power transistor MJ in association with R1 and R3 act as current sensor and amplifier, with maximum current capacity of 5 Amps. For acquiring higher output currents, the transistor, R1 and R3 may be adjusted proportionately.
The transistor may require a heatsink. The application is best suited for building high end type power supply units with excellent specifications and as battery chargers for charging all types of lead acid or SMF batteries. As can be seen in the diagram the IC LM hardly incorporates any external components, just a couple of them C1 and R1 to be precise.
C1 ensures ripple filtration and smoothes the input DC. Here the value ensures that the output current cannot rise beyond 1 Amp. Other values can be appropriately and proportionately worked in place of R1 for getting other desired control levels of the output current. As the circuit is protected from invalid current levels, it becomes suitable for applications where operations at strict or critical current levels become imperative.
The circuit can be also be used for charging cell phone batteries cell phones , automobile batteries, Ni-Cd batteries, for driving green pointer lasers, and for driving vulnerable high efficiency white LED lamps. The circuit is configured to produce precise 5 volt output ideally suitable for all logic circuits especially TTL circuits. The selected values of R1 and R2 here fixes the output to the required 5V, R2 may be altered with other relevant values for acquiring other desired output voltages, though.
The transistor has been included specifically for the shut-down operation. Under unfavorable conditions an external trigger switches the transistor into action which conducts and shorts R2 to instantly bring down the output to zero volts. Since the circuit is equipped with the feature of switching off through an external trigger, becomes extremely suitable for many critical circuit allplications where fool proof shut down facilities are felt to be an absolute necessity.
High Current Adjustable Regulator This configuration also provides the usual regulated, stabilized variable voltage output using LM, however here the current output is immensely increased and thus becomes suitable with circuits involve huge currents at desired settable voltages.
The maximum amount of current can be set by appropriately dimensioning the value of R1.
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