Question: Why Is VBE 0.7 V?

What is base emitter voltage?

One of the constraints on transistor action is that this voltage remains at about 0.6 volts (often referred to as the diode drop).

A small change in VBE can produce a large change in collector current and achieve current amplification..

What is VA in transistors?

VA is the Early voltage (as stated previously). On the Ic vs Vce plots typically shown for transistors (with variations in Vbe), the saturation region data can be linearly extraploated (backwards) and they will all approximately intersect at the same point on the (negative) xaxis. The intersection is at -VA.

When a transistor is saturated the collector current is maximum?

When the transistor operates in the Saturation then the voltage between collector and emitter terminal (Vce) is very low (typically it is 0.1 to 0.2 V), and the collector current Ic is maximum.

What is ΒDC equal to?

βdc is the amplification factor by which the base current gets amplified by. So the total output current, IC will be IC=βdc x IB.

How is IC Calculated?

Ic = collector current (amps) Ib = base current (amps) Example: A transistor has a current of 0.5 amps flowing through the collector and 0.02 amps though the base. Determine the value of the current gain. Note that gain has no units because it is a ratio.

Why is emitter always forward biased?

When the base emitter junction is forward biased and the collector/base junction is reverse biased, the electrons move from the n-type region towards the p-type region and the holes move towards the n-type region. When they reach each other they combine enabling a current to flow across the junction.

What is VA in Mosfet?

Similarly for MOSFET transistor, r DS= VA/ IDsat, Where rDS is the large signal drain to source resistance, IDsat is the drain saturation current and VA is the Early voltage of the MOSFET transistor.

What is the proper method of biasing a transistor?

The correct biasing point for a bipolar transistor, either NPN or PNP, generally lies somewhere between the two extremes of operation with respect to it being either “fully-ON” or “fully-OFF” along its DC load line. This central operating point is called the “Quiescent Operating Point”, or Q-point for short.

How do I get VBE?

Vbe ranges from 0.6 to 0.7 V for a silicon transistor. Assume Vbe = Vb = 0.7 V. Using Kirchhoff’s Law for the left-hand base loop, Vr = Vbb — Vbe = 3 V — 0.7 V = 2.3 V. Calculate “Ib,” the current through the base resistor.

What is the cutoff region?

Cutoff region This is the region in which transistor tends to behave as an open switch. The transistor has the effect of its collector and base being opened. The collector, emitter and base currents are all zero in this mode of operation. The following figure shows a transistor working in cutoff region.

What is NPN vs PNP?

PNP sensors produce a positive output to your industrial controls input, while NPN sensors produce a negative signal during an “on” state. … NPN, or “sinking” output sensors, work in the opposite way, sinking ground voltage to an input when it’s on.

What is a saturated transistor?

Saturation is the on mode of a transistor. A transistor in saturation mode acts like a short circuit between collector and emitter. In saturation mode both of the “diodes” in the transistor are forward biased. That means VBE must be greater than 0, and so must VBC. In other words, VB must be higher than both VE and VC.

What is CC configuration?

Definition: The configuration in which the collector is common between emitter and base is known as CC configuration. In CC configuration, the input circuit is connected between emitter and base and the output is taken from the collector and emitter.

What is early effect in a transistor?

Early effect or base width modulation: The early effect is the variation in the width of the base in a bipolar transistor due to a variation in the applied base-to-collector voltage. For example a greater reverse bias across the collector- base junction increases the collector-base depletion width.

What is the value of VBE?

VBE is the voltage that falls between the base and emitter of a bipolar junction transistor. VBE is approximately 0.7V for a silicon transistor. For a germanium transistor (which is more rare), VBE is approximately 0.3V.

Why VCE SAT is 0.2 V?

Because the charge carriers injected from the base effectively eliminate the depletion zone between the collector and emitter. The collector current doesn’t have to overcome the P-N junction potential because the base current has neutralized it.

How much is VCE when a transistor is saturated?

“Saturation” in a transistor switch circuit is achieved when the voltage across the collector/ emitter (VCE(sat)) is less than or equal to . 1 to . 3 volts – depending on the type of transistor. At that voltage point, the transistor appears to act like a simple SPST mechanical switch that has been closed (On).

When a transistor is used as a switch it is stable in which two distinct regions?

When a transistor is used as a switch, it is stable in which two distinct regions? 8. base junction transistor. binary junction transistor.