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The approximate voltage across the forward-biased base-emitter junction is 0.7 volts.
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When temperature increases voltage across diode with constant current?
The voltage across a semiconductor diode (and across the base/emitter junction of a transistor) decreases as temperature increases: the actual figure is -2mV/°C.
What component develops the output signal in a common emitter amplifier?
The voltage drop across the emitter-collector junction develops the output signal with the help of a resistor or two in series. The output is 'seen' at the collector.
Why does the emitter bypass capacitor increase the voltage gain?
In the common emitter configuration, gain is hFe or collector resistance divided by emitter resistance, whichever is less. Placing a capacitor across the emitter resistor effectively makes the emitter resistor less, for higher frequencies, so the gain is higher for higher frequencies. This creates a high pass filter, or a low cut filter, depending on what you want to call it.
What is use of capacitor Ce across emitter resistance?
It can be used as a feedback and to ground unwanted signals and frequencies
Why is the voltage across a battery in a parallel circuit equal to the voltage across each bulb?
The voltage across a battery in a parallel circuit is equal to the voltage across each bulb because Kirchoff's Voltage Law (KVL) states that the signed sum of the voltages going around a series circuit adds up to zero. Each section of the parallel circuit, i.e. the battery and one bulb, constitutes a series circuit. By KVL, the voltage across the battery must be equal and opposite to the voltage across the bulb. Another way of thinking about this is to consider that the conductors joining the battery and bulbs effectively have zero ohms resistance. By Ohm's law, this means the voltage across the conductor is zero, which means the voltage across the bulb must be equal to the voltage across the battery and, of course, the same applies for all of the bulbs.
Why common emitter amplifier gives phase reversal?
A: Because it is a voltage amplifier the current will inversely reflect the voltage across a resistor
When temperature increases voltage across diode with constant current?
The voltage across a semiconductor diode (and across the base/emitter junction of a transistor) decreases as temperature increases: the actual figure is -2mV/°C.
Why bypass capacitor is used in common emitter ampifier circuit?
If a bypass capacitor is used the voltage drop across emitter resistance is reduced which in turn increases the gain.....
What is emitter biasing?
Emitter biasing is when you add a resistor between the emitter of a transistor and the 0v rail so that any voltage developed across the emitter will subtract from the voltage on the base and effectively turn the transistor OFF. We are talking about an NPN transistor and the transistor is an "ordinary transistor" or BJT (bi-polar Junction Transistor). For more information on transistor biasing see: Talking Electronics website.
When testing transistors how much minimum voltage difference should be seen across the base-emitter junction?
It depends on the transistor. Minimum base-emitter junction voltage can be as low as 0.6 volts for a silicon transistor, and as low as 0.2 volts for a germanium transistor.
What component develops the output signal in a common emitter amplifier?
The voltage drop across the emitter-collector junction develops the output signal with the help of a resistor or two in series. The output is 'seen' at the collector.
When tesing a transistors how much minimum voltage difference should be seen across the base emitter junction?
Generally about 0.6V, but it could be a bit higher, 0.7 or so, if the base/emitter current is high.
What is vce and ie of a transistor?
A: Vce is the voltage across the transistor . Ie is the emitter current. Ico is the collector current with the base open. Or really the leakage.
Why phase shift of ce configuration is 180 out of phase while cc has same phase?
In a ce amplifier, an increase of base voltage causes the collector current to rise. This causes an increased voltage drop through the collector load resistor, so the collector voltage drops. With a cc amplifier the increase in current causes more voltage across the emitter load resistor, therefore the emitter voltage rises.
What is the phase relationship between the input and output voltage of a common emitter amplifier?
In common emitter amplifier circuit, input and output voltage are out of phase. When input voltage is increased then ib is increased, ic also increases so voltage drop across Rc is increased. However, increase in voltage across RC is in opposite sense. So, the phase difference between the input and the output voltages is 180 degrees.
Transistor as an amplifier common emitter configuration explanation using kirchhof's law?
Kirchoff's current law states that the current in every point in a series circuit is the same. In the case of a transistor in common emitter configuration, you can take advantage of that fact and state that the collector current is equal to the emitter current. The truth is somewhat different, because the gain of the transistor is not infinity, so the base current must be added to the emitter current. With a reasonably high gain, however, you can ignore the base current. Consider that the emitter voltage is related to the base voltage by the forward drop of the base-emitter junction, about 0.7 volts, and the collector and emitter currents are the same. Now look at the collector and emitter resistors. If the currents are the same, and the voltage across the emitter resistor is known, then you know the voltage across the collector resistor as well. This is an application of both Kirchoff's and Ohm's laws. The gain, then, of this amplifer is collector resistance divided by emitter resistance. It is an inverting amplier in this configuration. In some configurations, the emitter resistor is zero ohms. This does not mean the gain is infinity - it now means that the gain is limited by the gain of the transistor, which it is anyway - the emitter resistor is used to stabilize the gain and reduce dependency on individual transistor gains, which do vary.
Why does the emitter bypass capacitor increase the voltage gain?
In the common emitter configuration, gain is hFe or collector resistance divided by emitter resistance, whichever is less. Placing a capacitor across the emitter resistor effectively makes the emitter resistor less, for higher frequencies, so the gain is higher for higher frequencies. This creates a high pass filter, or a low cut filter, depending on what you want to call it.
