Light Bulb Resistance
Light Bulb Resistance - Related Videos
02:52
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Source: Wang, Y., et al. In Vivo Investigation of Antimicrobial Blue Light Therapy for Multidrug-resistant Acinetobacter baumannii Burn Infections Using Bioluminescence Imaging. J. Vis. Exp. (2017)This video demonstrates the procedure for treating burn wound infections caused by bioluminescent, drug-resistant bacteria in mice using blue light therapy, followed by bioluminescence imaging to monitor treatment efficacy.
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Imaging Odor-Evoked Activities in the Mouse Olfactory Bulb using Optical Reflectance and Autofluorescence Signals
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Cited by 9 •
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This article presents the protocols of intrinsic optical signals and flavoproteins autofluorescence signals imaging to map odor-evoked activities at the surface of the olfactory bulb in mice.
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Cited by 3 •
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Here we describe a protocol for measuring and analyzing temperature responses in the olfactory bulb of Xenopus laevis. Olfactory receptor neurons and mitral cells are differentially stained, after which calcium changes are recorded, reflecting a sensitivity of some neural networks in the bulb to temperature drops induced at the nose.
06:32
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Olfactory sensory neurons express a wide variety of axon-sorting molecules to establish proper neural circuitry. This protocol describes an immunohistochemical staining method to visualize combinatorial expressions of axon-sorting molecules at the axon termini of olfactory sensory neurons.
08:18
Targeting Olfactory Bulb Neurons Using Combined In Vivo Electroporation and Gal4-Based Enhancer Trap Zebrafish Lines
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Cited by 8 •
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The temporal and spatial resolution of genetic manipulations determines the spectrum of biological phenomena that they can perturb. Here we use temporally and spatially discrete in vivo electroporation, combined with transgenic lines of zebrafish, to induce expression of a GFP transgene specifically in neurons of the developing olfactory bulb.
FAQs
At switch-on, the tungsten filament is relatively cool, so its electrical resistance is lower than it is during normal operation. The lower resistance permits a larger current for the applied voltage. As current heats the filament, its resistance rises, reducing the current toward a steady operating value. This changing current is a direct consequence of temperature-dependent resistance.
An ohmic component maintains a constant resistance, so current changes proportionally with voltage. In an incandescent bulb, increasing voltage changes the current and also heats the tungsten filament. Because the hotter filament has greater resistance, the proportional relationship does not remain constant. The resulting current-voltage behavior is nonlinear, showing why the bulb cannot be treated as an ideal fixed resistor.
Cold resistance refers to the resistance of the filament before electrical heating has raised its temperature. Operating resistance is measured after the filament reaches its normal hot condition and is therefore higher. Comparing these values shows how strongly temperature affects the component. The difference also explains why resistance calculated from startup conditions may not represent steady circuit behavior.
Brightness depends on the electrical power delivered to the bulb. Power represents the rate at which electrical energy is converted, with the filament producing both light and heat as it operates. Changing the circuit voltage or current changes the power and can alter brightness, while the filament’s temperature-dependent resistance influences how those electrical quantities adjust during operation.
Students can measure the voltage across the bulb and the current through it at several operating conditions, then compare the resulting values. For each condition, resistance can be determined from the voltage-to-current ratio. Repeating measurements across changing electrical input reveals whether the ratio remains constant or varies, allowing the bulb’s nonlinear behavior to be identified from experimental data.
A current-voltage data set shows how the bulb responds as electrical conditions change. If the voltage-to-current ratio increases at higher operating points, the data indicate that the filament has become hotter and more resistive. Comparing low-input and steady-operation measurements therefore helps distinguish transient startup behavior from the conditions reached during normal use.
The bulb provides a practical example of how circuit variables connect electrical behavior with energy conversion. Measurements of voltage, current, and power show how electrical energy becomes light and heat, while the changing resistance explains why energy use cannot always be predicted with a fixed-resistance model. This makes the bulb useful for interpreting real circuit performance in physics.
A fixed-resistor model is inadequate when the bulb’s temperature changes significantly during operation, because the filament resistance then changes with that temperature. For startup analysis, varying-voltage measurements, or interpretation of a current-voltage graph, the non-ohmic model is more appropriate. A fixed-resistance approximation may describe only a selected operating condition, not the bulb’s entire behavior.