ADC limiter for ESP8266

229

04:50:29

First the resistor and Zener limits the voltage to 3.3 or 5 Volts.
Now that we have a known max voltage,
a voltage divider takes it down further to approximately 1.02 V so that the sensitive ADC pin is reasonably safe.

The voltage divider can probably be made with much lower resistances and still keep the max current within the tolerances of the ADC pin on the ESP8266 IC.

Potential improvements:
Reverse voltage protection (not sure what the max neg' voltage for the ADC pin is),
"over-voltage" indicator LED in line with Zener (LED Vf + Zener Vbreakdown = max V, beware of current spikes).

published 9 years ago

diman5777

9 years ago

Ок))

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.