Transistor and an LED in parallel

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Using a transistor as a low-side switch requires proper circuit configuration to ensure the LED lights up without shorting the circuit. The current should flow from the power supply through a current-limiting resistor, then through the LED and the transistor to ground. The placement of components, such as the resistor, is crucial for functionality. For further understanding, users are encouraged to search for typical transistor switch circuits online. Properly configuring the circuit will allow the LED to illuminate as intended.
physsure
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Hi! I'm new to EE and was wondering if this: https://imgur.com/a/lSgNl52 would cause the LED to light up, or would the transistor short the circuit?

(I forgot to add the arrow on the diode and I'm too lazy to fix it. And I just realized that the resistor is wrongly placed.)
 
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physsure said:
Hi! I'm new to EE and was wondering if this: https://imgur.com/a/lSgNl52 would cause the LED to light up, or would the transistor short the circuit?

(I forgot to add the arrow on the diode and I'm too lazy to fix it. And I just realized that the resistor is wrongly placed.)
Nope, doesn't work that way. When the transistor turns on as a "low-side switch", you want current to be drawn from the + power supply, through a current-limiting resistor, through the LED and the transistor to ground.

See if you can use Google Images to find typical circuits that do this. Let us know if you have trouble with the search terms and we can suggest some... :smile:
 
I am trying to understand how transferring electric from the powerplant to my house is more effective using high voltage. The suggested explanation that the current is equal to the power supply divided by the voltage, and hence higher voltage leads to lower current and as a result to a lower power loss on the conductives is very confusing me. I know that the current is determined by the voltage and the resistance, and not by a power capability - which defines a limit to the allowable...

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