I am trying to power-on my ESP82666 and it draws about 300ma on a 3.3v.

Can I power it up just like this, but instead put some sort of 2n2222 in place of the other transistors?

BTW: I am new to electronics, and I am learning a great deal, so please be patent with me.

Here is a simular post: How can I turn off a 3.3V circuit with a 3.3V microcontroller, and someone is trying to sort of do the same, but with different logic.

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    \$\begingroup\$ fig 1 is a switch to cut off or on 3.3v supply to the ESP8266, fig 2 is a line driver for data signals. \$\endgroup\$ – Wesley Lee Aug 16 '16 at 18:36
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    \$\begingroup\$ The second circuit will not work. Current from V1 will flow through Q1's E-B to Q2's B-E and partially short out the supply until one of the transistors fails (if the current is high enough). This is commented on your original post. \$\endgroup\$ – Transistor Aug 16 '16 at 19:10

Make your life easy. Read the datasheet for the ESP8266.

Page 27 tells you to use CHIP_PD to turn it on and off.

Page 12 lists all the pins and describes them. There's no CHIP_PD listed, but CHIP_EN is there with the same description.

When it says that pin sends it to low power mode, it really means it. Setting that pin to disable the ESP8266 drops current draw down to 0.5 microamperes. That ought to do ya.

Also note, this suggestion was also made in an answer to the linked question.

Doing it the way it was designed to be done saves you a transistor and debugging if you conect it wrong.


As @WesleyLee has commented, the first controls the power and the second level shifts the data. If you are running everything at 3.3V then you don't need to level shift the data.

To switch the power using a high side switch (as that arrangement in the first circuit is known) a 2N2222 is not suitable. That is an NPN transistor, and you would require a PNP transistor or preferably, as is shown in the circuit, a P-channel logic level MOSFET.

  • \$\begingroup\$ What is a good type of PNP transistor model number should I be looking for? By the way, thank you everyone! \$\endgroup\$ – Bill Daugherty Aug 16 '16 at 20:33
  • \$\begingroup\$ 2N2907 (or PN2907) should be a good choice, or the 2N3906 you've already mentioned. \$\endgroup\$ – BobU Aug 17 '16 at 17:41

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