user31105: I bought an ESP-01 adapter (initially I thought this was the WIFI module):
ESP-01 adapter
Than I bought the 'real'  ESP-01 (which is not arrived yet):
ESP-01
However, according to this link: connect (sorry it's in Dutch), but the picture shows that the ESP-01 is directly connected to the 3.3V of the Arduino.
My question: why bother using the adapter card? Or does it give additional security/protection (and what)?

user4143: Using an ESP8266 with a traditional Arduino requires logic level translation of the UART signal. That is what this adaptor provides. It also provides a dedicated 5V -> 3.3V voltage regulator so you don't stress the Arduino's rather underpowered 3.3V regulator.
The two SOT-23 components are N-channel MOSFETs (probably BSS138P or similar), and the SOT-89 component is the voltage regulator.
Yes, you can provide all that yourself, to varying levels of complexity - this just makes things easier. And since you already have it you may as well make use of it.

31105: <p>I bought an ESP-01 adapter (initially I thought this was the WIFI module):</p>

<p><a href="https://www.aliexpress.com/item/ESP8266-Serial-WiFi-Wireless-ESP-01-Adapter-Module-3-3V-5V-Compatible-For-Arduino/32740663668.html?spm=2114.13010608.0.0.90dm9a" rel="nofollow noreferrer">ESP-01 adapter</a></p>

<p>Than I bought the 'real'  ESP-01 (which is not arrived yet):</p>

<p><a href="https://www.aliexpress.com/item/Cr2032-battery-3v-cr2032-lithium-battery-button-cell-battery-electronic-2032-battery-electronic/1678385231.html?spm=2114.13010608.0.0.wrwcB5" rel="nofollow noreferrer">ESP-01</a></p>

<p>However, according to this link: <a href="http://domoticx.com/esp8266-wifi-esp-01-module-aansluiten/" rel="nofollow noreferrer">connect</a> (sorry it's in Dutch), but the picture shows that the ESP-01 is directly connected to the 3.3V of the Arduino.</p>

<p>My question: why bother using the adapter card? Or does it give additional security/protection (and what)?</p>
 4143: <p>Using an ESP8266 with a traditional Arduino requires logic level translation of the UART signal. That is what this adaptor provides. It also provides a dedicated 5V -> 3.3V voltage regulator so you don't stress the Arduino's rather underpowered 3.3V regulator.</p>

<p>The two SOT-23 components are N-channel MOSFETs (probably BSS138P or similar), and the SOT-89 component is the voltage regulator.</p>

<p>Yes, you can provide all that yourself, to varying levels of complexity - this just makes things easier. And since you already have it you may as well make use of it.</p>
