Update docs/index.md

docs/index.md

@@ -20,9 +20,9 @@ Electrostatic discharge can irreparably damage electronic devices. Use O-ESD wit
 * 15 hours of continuous operation (using fully charged 3200 mAh batteries).
 
 ## Quick-start guide
-The O-ESD is powered up (or down) using the toggle switch located on the grip. The O-ESD user interface consists of: toggle switch (ON/OFF), fire button, USB battery chargers (optional), LCD, down button, up button, multi-purpose knob located on the left side of the LCD.<br>
+The O-ESD is powered up (or down) using the toggle switch located on the grip. The O-ESD user interface consists of: toggle switch (ON/OFF), fire button, USB battery chargers (optional), LCD, down button, up button, and multi-purpose knob located on the left side of the LCD.<br>
 ![Grip](img_grip.png)<br>
-Once the O-ESD is powered-up the splash screen should appear for 1&nbsp;s at the LCD. Afterwards, the main screen of the O-ESD shows up. LCD has four 20-character lines. Each line stands for one item. Items (i.e., lines) are selected by moving the selector “ > ” using up/down buttons.<br>
+Once the O-ESD is powered up the splash screen should appear for 1&nbsp;s at the LCD. Afterwards, the main screen of the O-ESD shows up. LCD has four 20-character lines. Each line stands for one item. Items (i.e., lines) are selected by moving the selector “ > ” using up/down buttons.<br>
 If an item has a numeric value selectable by the user, the numeric value can be changed by rotating the knob. Some items have multiple choices (selections) or submenus (sub-items) available and those are accessible by pressing the knob.<br>
 ![UI](img_UI.png)<br><br>
 There are two modes of operation<br>
@@ -32,9 +32,9 @@ There are two modes of operation<br>
 <br>Screen (menu) has four items.<br>
 (1) The first (top) item on LCD is the battery status. It displays the minimum of relative voltages of the two batteries. If the voltage of a battery drops below 3.5&nbsp;V, the battery status displays that recharge is needed. Note that O-ESD will work even with very low battery voltage that may irreparably damage the batteries. Battery status has a submenu that presents extended information about each battery.<br>
 ![Battery_extended](img_bat_ex.png)<br>
-(2) The second item is the operation mode. It can be either contact or air as selected by the used.<br><br>
+(2) The second item is the operation mode. It can be either contact or air as selected by the user.<br><br>
 (3) The third item is the ESD voltage level. The ESD voltage can be in the range from –12&nbsp;kV to 12&nbsp;kV in the case of contact discharge, or in the range from –15&nbsp;kV to 15&nbsp;kV in the case of air discharge. Note that the sign of the charge (polarity) is defined by the position of the cascade, i.e., it should be placed in the correct position in order that given polarity can be produced at the output.<br><br>
-(4) The forth item (at the bottom of LCD) is<br>
+(4) The fourth item (at the bottom of LCD) is<br>
 (4a) the total number of pulses in the case of the contact discharge or<br>
 (4b) the hold time in seconds for air discharge (i.e., the time window in which the rounded tip is at the predefined voltage until the air discharge happens).<br>
 Once the user has selected the mode of operation, ESD voltage level and number of pulses (or hold time), the discharge is initiated by pressing the fire button on the grip. During all the specified discharge(s) cycles, the information about discharge is displayed on LCD and the O-ESD main screen is inaccessible.<br><br>
@@ -50,8 +50,8 @@ O-ESD consists of six parts:<br>
 (4) Shaper.<br>
 (5) Claws and strap.<br>
 (6) Motherboard.<br>
-Bill of materials (BOM) is available at link.<br>
+Bill of materials (BOM) is available at the link.<br>
-Design files are available at link.<br>
+Design files are available at the link.<br>
 ![Mechanical_parts_front](img_mechanical_parts_front.png)<br><br>
 ![Mechanical_parts_back](img_mechanical_parts_back.png)<br><br>
 ![Mechanical_front](img_mechanical_front.png)<br><br>
@@ -93,18 +93,18 @@ The transformer has the following roles<br>
 <br>Windings:<br>
 (1) The primary and the secondary are to be wound on the coil former.<br>
 (2) The total number of turns for the primary winding is 4.<br>
-(3) The total number of turns for the secondary winding is 1860, i.e., about 155 per layer, 12 layer in total.<br>
+(3) The total number of turns for the secondary winding is 1860, i.e., about 155 per layer, 12 layers in total.<br>
 (4) The sense (direction) of the windings should be the same.<br>
 (5) The high voltage (secondary) winding shall be wound first. The low voltage (primary) winding shall be wound on top of it.<br>
 ![Trafo_ends](img_trafo_ends.png)<br><br>
 Winding can be performed using a winding machine or produced manually, with care. The number of turns per layer of the secondary winding can be counted or can be estimated from the inside length of the coil former and the wire AWG.<br>
-<br>Regardless of the winding method, the beginning of the high voltage coil, which comes closest to the ferrite core, shall be inserted in heat shrink tubing and the tubing shall be heated to its final dimensions. The tubing is used to improve the insulation between the wire at the beginning of the coil and other wire layers.<br>
+<br>Regardless of the winding method, the beginning of the high-voltage coil, which comes closest to the ferrite core, shall be inserted in heat shrink tubing and the tubing shall be heated to its final dimensions. The tubing is used to improve the insulation between the wire at the beginning of the coil and other wire layers.<br>
 <br>Once a winding layer is completed, it shall be fully covered by layers of insulation paper. The total thickness of the insulating layer must be at least 0.2 mm. The first role of this insulation is to reduce the parasitic capacitances between adjacent wire layers. The second role is to increase the breakdown voltage between adjacent wire layers.<br>
 <br>The completed secondary winding shall be covered by layers of insulation paper either fully or only in the area where the primary winding is going to be placed. The main role of this insulation is to increase the breakdown voltage between the two windings.<br>
 <br>Once both windings are completed, the insulation from all wire ends shall be removed. Solder the terminals of the primary and secondary windings according to raster view. The beginning of the secondary winding (which is covered by the heat shrink tubing) shall be soldered to the pin denoted by the red circle in raster view.<br>
 <br>Insert the two halves of the ferrite core into the coil former shown in assembly of the step-up transformer. The cross sections of the core in the areas denoted by green ellipses should have gaps of 0.25&nbsp;mm to 0.3&nbsp;mm. Cut three pieces of the standard printing paper (80&nbsp;GSM) per gap, and stack pieces to form the gap. It is not necessary to place the paper in the central column of the core.<br>
 ![Trafo_core_clips](img_trafo_core_clips.png)<br><br>
-Secure the transformer by two clips. One clip is shown in Sketch of a clip. The location of the clips can be seen in assembled step-up transformer.<br>
+Secure the transformer with two clips. One clip is shown in Sketch of a clip. The location of the clips can be seen in assembled step-up transformer.<br>
 
 ## Use-case scenarios for testing and demonstration
 Five use-case scenarios for electrostatic-discharge testing and demonstration of ESD effects are [presented](https://o-esd.etf.bg.ac.rs/forgejo/dragan.olcan/O-ESD/src/branch/main/Demos#).<br>