L7800 SERIES

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Figure 35: Adjustable Output Voltage with Temperature Compensation

Figure 37: Protection against Input Short-Circuit with High Capacitance Loads

Application with high capacitance loads and an output voltage greater than 6 volts need an external diode (see fig. 33) to protect the device

against input short circuit. In this case the input voltage falls rapidly while the output voltage decrease slowly. The capacitance discharges by

means of the Base-Emitter junction of the series pass transistor in the regulator. If the energy is sufficiently high, the transistor may be de-

stroyed. The external diode by-passes the current from the IC to ground.