Basics of electronics-matters and fields

Matters and fields


Charge, Fields, Voltage, Current, and Beams:


Review main points: This should be a review for those who have taken High school
Physics or have read a book on physics or electricity.
1. Conventional current flows in the direction of E field. That is it flows from positive to
negative potential. From here on "current flow" means conventional current flow.
2. Current normally flows in the direction of arrows on transistors and diode symbols.
3. Current in wire and resistors is due solely to electron flow.
4. Current in transistors and diodes is due to hole flow (positively charged molecules) and
electron flow. The holes and the electrons move towards each other.
5. Positive charged particles flow in the direction of current and E fields.
6. Negative charged particles flow in opposite direction of current or E fields.
7. The EMF of a battery forces positive ions to move to the positive plate of a battery.
8. The EMF of a battery forces negative ions to move to the negative plate of a battery.
9. Holes (positively charged molecules) in silicon crystal lattice carry charge in
semiconductors and move in direction of current. Current is in the direction of E field.
Current direction is indicated by direction of arrow on transistor or diode.