Flickering İncandascent Lamp

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electrics

Senior Member
Hi, What causes the flickering of incandascent lamps? İt is said that loose connection does so, I wonder if it has to do with bad neutral also. The real aim is to learn why bad connection (if it is so) causes flickering physically? I can not explain the increase and decrease of the light of the lamp with bad connection...
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
101123-0615 EST

Consider a series circuit of a battery, resistor R1, and a second resistor of R2. Battery voltage is constant. R2 is the lamp bulb. Assume R2 constant, it is not, but this assumption is adequate for your question.

Change R1 from 0, full voltage to R2, to some value larger than 0, for example equal to R2. This reduces the voltage to R2. Lower voltage on R2, the lamp, reduces its brightness.

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BILLY101

Member
Location
Telford, Pa
120 volt loads are sometimes (2) 120 volt loads in series across 240 volts with the neutral providing a route for the current difference (imbalance) of the (2) loads.
If the neutral is not solidly connected or is undersized the switching of one load can cause the other load (lamp) to become brighter or dimmer depending on which load is greater and the impedance of the neutral (poor connection).
The flickering could be caused by a motor starting.
In residential services it is common to experience a loose neutral in the meter socket.

BILLY
 

electrics

Senior Member
pls just tell me for a simple phase neutral circuit, does poor connection or poor touch of lamp base to the lamp causes permanent flickering ? if so why this resistance (due to poor touching )changes? "flickering" means a resistance increases and decreases continually, this is what I dont understand...
 
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Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Vibration. Expansion and contraction of the metals in the lamp.base. If this is just one fixture tear it apart until you understand. If the whole house look for loose connections at service. This could be a POCO problem. Look for a load that is cycling to cause the vd.
 
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