Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy.

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our Privacy Policy and User Agreement for details.

Like this presentation? Why not share!

- Current Electricity by OhMiss 4547 views
- Midia como fazer um planejamento de... by profjucavalcante 5745 views
- We are mad about ELECTRICAL ENGINE... by Surendra Suri 605 views
- Static electricity 1008 by Mr. M 2452 views
- Electrical engineering basic by jibril aga 2790 views
- Current Electricity by I Wonder Why Science 4447 views

1,002 views

778 views

778 views

Published on

No Downloads

Total views

1,002

On SlideShare

0

From Embeds

0

Number of Embeds

1

Shares

0

Downloads

68

Comments

0

Likes

9

No embeds

No notes for slide

- 1. Introduction toElectrical Engineering
- 2. GoalTo introduce the fundamental conceptsthat govern the principles andpractices of electrical andelectronics engineering.
- 3. Electron ‣ Negatively charged particle, revolves around nucleus of an atom. Electrons are repelled by other electrons.Absence of electron (hole) attracts electrons. Like charges repel, opposites attracts.
- 4. Static vs. Current ELectricity‣ Static Electricity ‣ Charge does not flow.‣ Current Electricity ‣ Charge flows along a conductor. ‣ Conventional Current Wisdom: Flows from higher potential to lower potential. ‣ Electron Flow Reality: Electrons are repelled by negative charge and attracted to positive charge.
- 5. Conductor vs. Insulator‣ Conductor: Allows electrons to flow. ‣ Copper Wire‣ Insulator: Prevents electrons from flowing. ‣ Rubber‣ Semiconductors behave as both. ‣ Silicon
- 6. The EE Basics‣ Voltage (V) ‣ Electric “pressure” or potential difference between two points. ‣ Must exist for current to flow. ‣ Volts - e.g. 2.5V ‣ Ground is nominally 0V, serves as a reference voltage.‣ Current (I) ‣ Rate of electrons flowing. ‣ Amperes or Amps - e.g. 5A
- 7. The EE Basics‣ Resistance (R) ‣ Measure of how much a material impedes current flow. ‣ Ohms - e.g. 500KΩ‣ Power (W) ‣ Measures the rate at which energy is consumed. ‣ Watts - e.g. 5mW
- 8. Direct vs. Alternating Current‣ Direct Current (VDC) ‣ Current flows in one direction.‣ Alternating Current (VAC) ‣ Current periodically changes direction. Frequency Amplitude Phase
- 9. Series vs. Parallel Circuits Series Current has only one path to flow from source to ground. Current around a series circuit is the same, voltage across each element varies based on its resistance. Parallel Current has multiple paths to return to ground. Voltage across parallel components is the same, current through each components varies based on its resistance.
- 10. Calculating Resistor Value for an LED We want to add a Light Emitting Diode to our circuit. What size resistor do we add in series to the LED for it to operate safely?
- 11. Find the “givens”: Battery or Source Voltage Vf or Forward Operating Voltage of the LED. Imax or maximum current of the LED. Both found in spec sheets. For our example assume: Vbattery = 5V Vf = 1.7V Imax = 20mA
- 12. Vbattery = 5V Vf = 0.7V Imax = 20mA Ohm’s Law R = V / IR = (Vbattery - Vf) / ImaxR = (5V - 1.7V) / .02AR = 165 ΩReality is you will NOT find a 165 Ω. Sofind the next LARGER value and use that.For our solution, 180 Ω resistors are fairlycommon.
- 13. Resistor value is HALF thestory.We must also ensure theproper POWER RATING.If we do not allow for thecorrect power dissipation,component could catch fire! Power = Voltage x CurrentFrom last slide, resistor will have to drop 3.3V and pass 20mA of current. Power (Watts) = 3.3V x .02A Power = 66mW
- 14. Again, you will not find aresistor rated for 66mW.Look for the next largervalue, typically 1/4W or250mW is readily available.So for our solution, we will need toacquire a 180Ω resistor rated at 250mW.
- 15. Questions?

No public clipboards found for this slide

×
### Save the most important slides with Clipping

Clipping is a handy way to collect and organize the most important slides from a presentation. You can keep your great finds in clipboards organized around topics.

Be the first to comment