Electrical – Voltage drops when load connected to ld1117a

esp8266low-powerpower electronicsvoltage-regulator

Package: LD1117A (package sot223)

Power: USB adapter( mobile charger ) 5.3 V 2 A

When these is not r1 resistor present and adj is connected to ground, Vout is 4.9 V for Vin 5.3 V.

r1 is 120 ohm and r2 is adjusted with 20 k potentiometer to get 3.46 V at output. Then load (essentially esp8266 01) is connected, voltage drops to 0.6v and even on adjusting potentiometer to full 20 k, vout just reaches 0.71 V.

Why is this happening?

How to resolve so that ESP8266-01 gets power up?

Datasheet See page 12

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Best Answer

The capacitor at the output is NOT optional. It is required for stability on most LDO regulators, including the semi-LDO LM1117.

However the roughly one diode drop 0.7V output suggests you may have connected the load in reverse and possibly damaged it in the process.