Chaca, i get it!:-)

Shardan, you was right! I needed just two diodes in line and now it's switching as it should!:-) I'm happy!
Thank you very much for your help!

And I make the test also. It's switch on when IN1 is on gnd.

Greetings
Thomas

IT's the following relay:
I bought it from Ebay. The Relay needs 5V power to work but the in1 power was not specified. To it sounds (for me) logical right that i need 5V vor in1 too. Or is this wrong?

Thank you for your answers, @Shardan yeah its exactly some kind of module you specified. I connected it directly with 5 volt power and the gpio with the port on the relais. So you means I just need 3 diodes (in the right direction of course!), put them in a line and it would work? Sorry, I'm an abso...

Hello, I'm sorry to get on your nervs with this (i hope so) simple problem. I have an esp8266-01 and tried to switch an relay on gpio2 following the explanation on https://www.letscontrolit.com/wiki/index.php/Relais. I could switch it on with http://<ip-adress>/control?cmd=GPIO,2,0 or 1 And thats th...