Why does LED2 light only half time compared to LED1?

  • Thread starter Thread starter StrongInterac
  • Start date Start date
  • Tags Tags
    Time
AI Thread Summary
LED2 lights only half the time compared to LED1 due to the behavior of the transistor in the circuit. When the Base voltage is high, the transistor allows current to flow between the Emitter and Collector, effectively acting as a switch. This results in one LED receiving current while the other does not, depending on the Base voltage state. When the Base voltage is low, the circuit becomes open, stopping current flow and affecting the LEDs' operation. Understanding the transistor's function clarifies the differing light times of the two LEDs.
StrongInterac
Messages
6
Reaction score
0
Can anyone explain to me why LED2 light only half time compared to LED1? If Us=2sinωt volts
 

Attachments

  • DSCN0263.JPG
    DSCN0263.JPG
    13.6 KB · Views: 501
Engineering news on Phys.org
Think about what the transistor does when Vs is "high".
 
it doesn't help me a lot...
 
That's okay, we'll review how the transistor functions in this circuit.

The transistor has 3 nodes:
The Base (left side of transistor)
The Emitter (lower-right of transistor)
The Collector (upper-right of transistor)

In this circuit, the transistor acts like a simple switch. When the Base voltage is high, you can treat it as a short between the Emitter and Collector. Which LED or LED's have any appreciable current going through them, if you short the Emitter to the Collector?

When the Base voltage is low or negative, you can treat the Emitter to Collector as an open circuit, with no appreciable current. If that's the case, which LED or LED's have an appreciable current going throw them?
 
I understand it now. Thx for the help!
 

Thread 'How might electronics be different if AC voltage was 72V at 45 Hz?'

Hey guys. I have a question related to electricity and alternating current. Say an alien fictional society developed electricity, and settled on a standard like 73V AC current at 46 Hz. How would appliances be designed, and what impact would the lower frequency and voltage have on transformers, wiring, TVs, computers, LEDs, motors, and heating, assuming the laws of physics and technology are the same as on Earth?
View full post »

Thread 'What happens if shielded cable has a short to the shield?'

While I was rolling out a shielded cable, a though came to my mind - what happens to the current flow in the cable if there came a short between the wire and the shield in both ends of the cable? For simplicity, lets assume a 1-wire copper wire wrapped in an aluminum shield. The wire and the shield has the same cross section area. There are insulating material between them, and in both ends there is a short between them. My first thought, the total resistance of the cable would be reduced...
View full post »

Thread 'Why does the amperage go real high if there is a low voltage short?'

I used to be an HVAC technician. One time I had a service call in which there was no power to the thermostat. The thermostat did not have power because the fuse in the air handler was blown. The fuse in the air handler was blown because there was a low voltage short. The rubber coating on one of the thermostat wires was chewed off by a rodent. The exposed metal in the thermostat wire was touching the metal cabinet of the air handler. This was a low voltage short. This low voltage...
View full post »

Similar threads

Connect: Coupling Light from 2 LEDs into a Single Fiber
Replies
2
Views
3K
Basic Circuit: Why don't these two LEDs light up?
Replies
9
Views
2K
12V DC Motor in Light Fixture with Dimmer & 12V DC to 110V AC Inverter
Replies
21
Views
2K
Question about Powering a lighting unit: 14 VDC @ 3.2A / 28VDC@ 1.6A
Replies
8
Views
2K
I Speed of light one more time
Replies
5
Views
1K
High inrush current for LED drivers
Replies
2
Views
2K
Why doesn't a light bulb draw 100 amps?
Replies
26
Views
4K
How is an autocorrelation function computed? (Dynamic Light Scattering)
Replies
1
Views
1K
I Bending of Light Along the Sun: Explaining Half w/ Equivalence Principle
Replies
15
Views
3K
Home Solar Power Feed-in Tariff for Historical Domestic Installations in the UK
Replies
7
Views
1K

Hot Threads

Recent Insights

Back
Top