A Soft Start Circuit prevents the sudden current flow in the circuit during the start. It slows down the rate of rising output voltage by minimizing the excess current flow during the start. It is useful to protect the devices or electronic components from the damage caused by instantaneous high input current. Some components which are current limited and having poor load regulation can get damaged because of this high input current. Here we are building the soft start circuit using a voltage regulator IC LM317 and a PNP transistor BC557.
Read the complete tutorial here: https://circuitdigest.com/electronic-circuits/soft-start-circuit-for-power-supply