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I was trying to run my ESP8266(iot device) by watching and learning from this video.

https://www.youtube.com/watch?v=9QZkCQSHnko (only 5 mins long)

Now in the video it is mentioned that the ESP chip requires 20mA-250mA of current.

The person uses a voltage divider circuit built through resistance to regulate the voltage.

He uses two resistors of 2k Ohms and 1k Ohms respectively. Now, the minimum resistance of the circuit connected to power supply, when the ESP is connected through parallel will still be greater than 1k Ohm (least lower bound) as you will connect the ESP through parallel to the 2k Ohm resistor.

Now the power supply was of 5v in the video, and by using Ohm's law, we would get a maximum current of 5mA. How can the chip work then?

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    \$\begingroup\$ I am not going to watch the video, but I can tell that using voltage divider as a power supply is a terrible idea, especially if the load current is not constant (and I bet this is the case for ESP_whatever). \$\endgroup\$
    – Eugene Sh.
    Oct 22 '15 at 21:11
  • \$\begingroup\$ @EugeneSh. How can one keep load current constant using a power supply? in reference to this question here. electronics.stackexchange.com/questions/34745/… \$\endgroup\$
    – Isomorphic
    Oct 22 '15 at 21:13
  • \$\begingroup\$ Why would one want to? The supply current depends on what the load needs. \$\endgroup\$
    – Eugene Sh.
    Oct 22 '15 at 21:15
  • \$\begingroup\$ @bitsmack op knows that a divider has those issues that's why he was confused. \$\endgroup\$
    – Passerby
    Oct 23 '15 at 0:30
  • \$\begingroup\$ And it's your name bit smack, or bits mack? @bitsmack \$\endgroup\$
    – Passerby
    Oct 23 '15 at 0:30
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Took me a few rewatches to understand him. The Voltage Divider is for the FTDI's Tx/ESP's Rx line, not the power. A 5V signal on the Rx line would kill the ESP, so it needs to be brought down. Since it's an input, likely High Impedance, it will barely affect the voltage divider, keeping the divider voltage at 3.2V as selected.

The power comes from a bench power supply set to 3.3V.

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  • \$\begingroup\$ Damn and I started watching this horrible video for nothing. \$\endgroup\$
    – Arsenal
    Oct 22 '15 at 21:24
  • \$\begingroup\$ @Arsenal Sorry :) \$\endgroup\$
    – Isomorphic
    Oct 22 '15 at 21:37

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