Altium Designer: Useful Shortcuts for Component Placement

  - Rotate counterclockwise by 90 degrees while moving an object: SPACEBAR
  - Align selected objects by top edges: SHIFT + CTRL + T
  - Distribute selected objects equally in the horizontal plane : SHIFT + CTRL + H
  - Align selected objects by left edges: SHIFT + CTRL + L
  - Align selected objects by right edges: SHIFT + CTRL + R
  - Distribute selected objects equally in the vertical plane : SHIFT + CTRL + V
  - Align selected objects to grid: SHIFT + CTRL + D
  - Align selected objects by bottom edges: SHIFT + CTRL + B

Altium Designer : Pcb Panelization

On the Place tab, Select Embedded Board Array/ Panelize. Click anywhere in the PCB area. Under the Properties menu, select your PCB and set the desired Column margin and Row spacing.

Altium Designer : Creating Board Outline From Mechanical Outline and Making Cutout Holes

Select Mechanical Outline. Under the Properties menu, Change the Mechanical outline layer to the user-defined board outline layer.
To create a custom board shape, select the board outline that has been created. On the Design Tab, in the board shape, select Define from selected Objects.
To create a cutout hole, select the desired outline. On the Tool Tab, in the Convert, select Create Boardcutout from selected primitives.

Altium Designer : Moving Design Origin to User's Preferred Location

On the Edit tab, in the Origin,  choose Set.

Altium Designer, Shortcuts for Viewing, Changing Grid and Snap Setting

Toggle measurement Unit: Q
Accessing Grid menu: G
Changing snap setting: SHIFT + E
Switching 2D and 3D View: 2 & 3
Fit all objects into view: CTRL + PAGE DOWN
Zoom in around the cursor (zooms around the cursor, position the cursor first): CTRL + Mouse-wheel up (or PAGE UP)
Zoom out: CTRL + Mouse-wheel down (or PAGE DOWN)

AAA Battery Protection with Wrong Polarity LED Indicator

This simple circuit will protect the AA or AAA battery from the wrong polarity connection to your device. If the battery is connected in the opposite way, D1 will conduct and PTC Fuse will break the circuit. Wrong polarity indicator, LED 1 will be turned on at the same time.