How do Transistors work? Almost like a flush toilet #Electronics #EE @startitup_
Start it up explores how transistors work, noting it’s similar to a flush toilet!
In a basic amplifier circuit the emitter is connected to a voltage source, such as a battery, while the collector is connected to the ground via a resistor. Injecting a small current into the base (labeled “B”), a large current is observed to flow between the emitter (labeled “E”) and the collector (labeled “C”), such that the voltage output on the right is large, too (see the picture above, on the left).
The net result is that you inject a small current in the base of the transistor and you see a large current flowing out of the collector, as if the input current were multiplied by some factor. In fact, the current observed at the output of the transistor is not the amplified input current, but another current, proportional to the input current, extracted from the voltage source. The transistor acts just as a switch, allowing current flowing from the voltage source to the ground, through the resistor.
An interesting analogy can be made between a transistor amplifier and a toilet (see the right-hand side of the picture above). The emitter is the flush cistern, while the collector is the toilet bowl. Imagine attaching a small bucket to the flush lever, which represents the base. Pouring a little water into the bucket is like injecting a current into the base of the transistor. The weight of the water poured into the bucket activates the lever and the toilet valve opens, allowing the water contained in the emitter/cistern (the analogue of the charges contained in the voltage source attached to the emitter of the transistor) to flow copiously into the collector/bowl, as if the device were multiplying the water poured into the bucket and letting it flow into the pipe (the analogue of the resistor).
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