diff --git a/notepad b/notepad
index 7a2bd48..267169c 100644
--- a/notepad
+++ b/notepad
@@ -1,3 +1,6 @@
+ADD varistance to protect power supply if high potential appear
+
+
 http://internetofhomethings.com/homethings/?p=530
 
 https://www.letscontrolit.com/forum/viewtopic.php?f=2&t=1078&p=5299&hilit=acs#p5299
@@ -7,3 +10,14 @@ https://hilo90mhz.com/remote-power-monitoring-system-ac-or-dc-current-measuremen
 http://www.ti.com/product/INA219/datasheet
 
 http://www.ti.com/lit/ds/symlink/ads1115.pdf
+
+
+https://www.letscontrolit.com/forum/viewtopic.php?f=4&t=627&hilit=PME+extender&sid=f064b3a5cda5f7cf9fee3ffc32a6de3e&start=20
+https://www.letscontrolit.com/forum/viewtopic.php?f=5&t=2126&hilit=AC+current
+
+
+https://easyeda.com/editor#id=f5fc1398138645be9c82e64f809283bd
+
+
+
+https://focus.ti.com/lit/ds/symlink/opa344.pdf