diff --git a/bbn_m5atomS3_lite_alternator_freq_to_RPM/README.md b/bbn_m5atomS3_lite_alternator_freq_to_RPM/README.md
index 3fe4fa8..62c6746 100644
--- a/bbn_m5atomS3_lite_alternator_freq_to_RPM/README.md
+++ b/bbn_m5atomS3_lite_alternator_freq_to_RPM/README.md
@@ -7,7 +7,7 @@ You can find them searching Internet for:
 
 817 optocoupler isolation module
 
-The circuit of the boars looks like this:
+The circuit of the boards looks like this:
 
 
 ![PC817 optocoupler isolation module board](img/PC817_optocoupler_circuit.png)