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Calculate the DC base current of a transistor circuit if the DC collector current is 4.9mA and the DC emitter current is 5mA?
Emitter current can be summed up by the formula: IE = IC+ IB Where IE = Emitter Current, IC = Collector Current, and IB = Base Current So simply take IE - IC and you'll get an IB of about 100uA. (5mA-4mA = .1mA or 100uA) Also, remember that IB controls IC and IE, not the other way around. You can also determine IB if Beta is known by the formula: IC = IB * Beta Which can be manipulated to equal IB = IC/Beta Hope this was helpful.
What percentage of the total current in a transistor flows through the collector?
The total current in a transistor is the emitter current, which is the sum of the collector current and the base current. The ratio of collector current over base current, in linear mode, is beta-DC, or hFe. However, in order for linear mode to be true, the ratings of the transistor must not be exceeded, and the collector current must not be limited by the circuit. Note also that hFe is temperature dependent, and is expressed in the data sheet as a minimum, not an absolute value - it can vary from transistor to transistor.
What should be the value of collector current in terms of DC gain if transistor is in saturation mode?
DC current gain is collector-emitter current divided by base-emitter current. In linear mode, gain is beta, or hFe. In saturation mode, however, the transistor is over-driven and you can no longer relate collector-emitter current to base-emitter current. The transistor operates like a switch, and collector-emitter current is a function of voltage and load impedance only. (Ignoring the relatively small voltage drop.) To maintain saturation mode, the collector-emitter current must be smaller than the base-emitter current times hFe. Often, it is several times smaller, because hFe can vary from transistor to transistor, and your design must account for this variability.
When is the collector current maximum?
The maximum collector current is normally rated to be the current at which the DC current gain (hFE) falls to 50% of its maximum value. The maximum peak current is Page 2 Operation notes Transistors Rev.A 2/7 rated at a value which ensures reliability within the maximum allowed junction temperature.
What are the two kinds electricity?
Perhaps you are referring to DC and AC? DC is direct current - current flows in a single direction. In AC (alternating current), the current regularly changes its direction.Perhaps you are referring to DC and AC? DC is direct current - current flows in a single direction. In AC (alternating current), the current regularly changes its direction.Perhaps you are referring to DC and AC? DC is direct current - current flows in a single direction. In AC (alternating current), the current regularly changes its direction.Perhaps you are referring to DC and AC? DC is direct current - current flows in a single direction. In AC (alternating current), the current regularly changes its direction.
Does a transistor allows control of large currents with small current signals?
Yes. The ratio of collector current and base current is DC gain, also known as beta, or hFe.
Calculate the DC base current of a transistor circuit if the DC collector current is 4.9mA and the DC emitter current is 5mA?
Emitter current can be summed up by the formula: IE = IC+ IB Where IE = Emitter Current, IC = Collector Current, and IB = Base Current So simply take IE - IC and you'll get an IB of about 100uA. (5mA-4mA = .1mA or 100uA) Also, remember that IB controls IC and IE, not the other way around. You can also determine IB if Beta is known by the formula: IC = IB * Beta Which can be manipulated to equal IB = IC/Beta Hope this was helpful.
What is the difference between alpha DC and beta DC?
Alpha direct current (DC) is the current consumed by electrical equipment when they are idle or in standby mode, while beta DC is the current consumed by electrical equipment during their operation. Alpha DC is also known as standby power consumption, whereas beta DC is related to the active power consumption of the device.
What percentage of the total current in a transistor flows through the collector?
The total current in a transistor is the emitter current, which is the sum of the collector current and the base current. The ratio of collector current over base current, in linear mode, is beta-DC, or hFe. However, in order for linear mode to be true, the ratings of the transistor must not be exceeded, and the collector current must not be limited by the circuit. Note also that hFe is temperature dependent, and is expressed in the data sheet as a minimum, not an absolute value - it can vary from transistor to transistor.
What should be the value of collector current in terms of DC gain if transistor is in saturation mode?
DC current gain is collector-emitter current divided by base-emitter current. In linear mode, gain is beta, or hFe. In saturation mode, however, the transistor is over-driven and you can no longer relate collector-emitter current to base-emitter current. The transistor operates like a switch, and collector-emitter current is a function of voltage and load impedance only. (Ignoring the relatively small voltage drop.) To maintain saturation mode, the collector-emitter current must be smaller than the base-emitter current times hFe. Often, it is several times smaller, because hFe can vary from transistor to transistor, and your design must account for this variability.
What is the formula to calculate beta DC?
beta dc= ic/ib!!
How do you draw DC load line and determine the Q point?
we should be take two point from the the graph between collector current and emitter-collector voltage.. along the horizontal line collector current is zero and emitter-collector voltage become Vcc,and along the vertical line emitter-collector voltage is zero and collector current become Vcc/RL then by this line that drow between this two point is called load line that in this line the transistor allowed to operate....
What is the gain of bc 547?
If you want to find DC gain (Hfe) of a BJT transistor like BC547, then you need to look in its datasheet. You can easily find a datasheet for BC547 just by googling it. Once you found it, then you will find a graph for DC current gain in the datasheet. The x-axis of the graph will be the collector current (Ic) and the y-axis will be the gain (Hfe). As you will see from the graph the gain is dependent on the collector current Ic. Therefore first determine what collector current you want to be flowing, then use the graph to find what the DC gain will be. Then you can find what base current Ib you need to inject in order to establish the necessary collector current Ic. The relationship is Ic = Hfe*Ib.
What are the two main characteristics of a transistor?
- The ratio of the dc collector current (IC) to the dc base current (IB) is thedc beta (bDC).- bDC is called the gainof a transistor:bDC = IC/IB- Typical values of bDC range from less than 20 to 200 or higher.- bDC is usually designated as an equivalent hybrid (h)parameter:hFE = bDC- The ratio of the collector current (IC) to the dc emitter current (IE) is the dc alpha (aDC). This is a less-used parameter than beta.aDC = IC/IE- Typical values range from 0.95 to 0.99 or greater.- aDC is always less than 1.- This is because IC is always slightly less than IE by the amount of IB.- From graph above we can see that there are 6 important parameters to be considered:i) IB: dc base current.ii) IE: dc emitter current.iii) IC: dc collector current.iv) VBE: dc voltage at base with respect to emitter.v) VCB: dc voltage at collector with respect to base.vi) VCE: dc voltage at collector with respect to emitter.- VBB forward-biases the BE junction.- VCC reverse-biases the BC junction.- When the BE junction is forward biased, it is like a forward biased diode:VBE ? 0.7 V- But it can be as high as 0.9 V (and is dependent on current). We will use 0.7 V from now on.- Emitter is at ground. Thus the voltage across RB isVR(B) = VBB- VBE- AlsoVR(B) = I­RRB- Or:I­RRB = VBB- VBE- Solving:IB = (VBB- VBE)/RB- Voltage at collector with respect to grounded emitter is:VCE = VCC - VR(C)- Since drop across RC is VR(C) = ICRC the voltage at the collector is also:VCE = VCC - ICRC- Where IC = bDCIB. Voltage across the reverse-biased collector-bias junction isVCB = VCE - VBEthank you
What is DC load line of a transistor?
A: A transistor has voltage gain as base current is allow to flow. If the load is constant then a DC mirror azimuth path can be plotted as a function of base current and collector current and that is the load line
When is the collector current maximum?
The maximum collector current is normally rated to be the current at which the DC current gain (hFE) falls to 50% of its maximum value. The maximum peak current is Page 2 Operation notes Transistors Rev.A 2/7 rated at a value which ensures reliability within the maximum allowed junction temperature.
How do you design a voltage divider bias circuit with certain specifications for Vcc Ic and beta-dc?
When you design a voltage divider bias circuit for a BJT amplifier, you must consider the base current, because that represents a resistance which is in parallel with the lower leg of the divider. To determine the base current, select the desired operating point, and calculate the emitter (collector) current. Divide that by beta-dc, and you have base current. Back calculate the effective base resistance, and build the divider accordingly. Note that in a silicon BJT, the base voltage is about 0.7 V higher (NPN) or lower (PNP) than the emitter. Note also that these calculations only work correctly when the BJT is in linear mode. Note also that beta-dc varies amongst BJT's, even though with identical designs, so your design must consider these variations - you can compensate with an emitter resistor, but variations still have an impact.
