From 6a40a32f875c049ffc8017a0411ba581f2bcf996 Mon Sep 17 00:00:00 2001 From: rajtan Date: Tue, 30 Aug 2022 23:27:05 +0530 Subject: [PATCH] Update README.md Just changed the description of the resistor. Earlier description, though grammatically correct, created an entirely different valid meaning, which was utterly confusing. --- README.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/README.md b/README.md index 9777a97..a304a3a 100644 --- a/README.md +++ b/README.md @@ -1,6 +1,6 @@ ## ESP8266 - Power Sensor (Using a Wemos D1 Mini) -The sensor PCB uses a split core current transformer (CT) to sense the AC current flowing through a mains cable, a typical CT would be the SCT-013-000 (Current Type) capable of measuring up to 100A available on eBay. The current transformers output is applied to a burden resistor (22 ohm) which is biased at around half of the ESP8266's supply voltage (3.3V). The ESP8266's own A/D is then used to measure voltage developed across this burned resistor. The A/D used in the ESP8266 has an input voltage range of 0-1V but the Wemos adds a resistor divider to allow for a 0-3.3V input range to the Wemos board. +The sensor PCB uses a split core current transformer (CT) to sense the AC current flowing through a mains cable, a typical CT would be the SCT-013-000 (Current Type) capable of measuring up to 100A available on eBay. The current transformers output is applied to a burden resistor (22 ohm) which is biased at around half of the ESP8266's supply voltage (3.3V). The ESP8266's own A/D is then used to measure voltage developed across this burden resistor. The A/D used in the ESP8266 has an input voltage range of 0-1V but the Wemos adds a resistor divider to allow for a 0-3.3V input range to the Wemos board. Included are the PCB files with schematic, a simple 3D printable case and some sample firmware for the ESP8266.