This magnetic field attracts a moving ferrous core material which is connected to a spring tension or gravitational pull. In earlier automobile generators and alternators contains mechanical regulators. A good voltage regulator may also include additional circuits for protection like short circuits, current limiting circuit, thermal shutdown, and overvoltage protection. This is because of the small value of the maximum collector emitter voltage of transistor 50 Volts. Like emitter follower regulator this regulator also has the drawback of excessive power dissipation. Controlled Transistor Series Regulator.

The Web This site. Tr1 base voltage rises, and increases the conduction of the control transistor. Under these conditions the output voltage will fall to zero for as long as the excess current condition persists, but the supply will be undamaged. If the output voltage increases, the shunt current increases and thus produces less load current and maintains a regulated output voltage. With the Zener diode connected to the transistor base in our example circuit, the voltage difference is denoted as:. The amount of this fall is about 0. If the output voltage tends to decrease, then so does V F.

Trqnsistorised a regular transformer, the CVT has a primary and a secondary. If the mechanical regulator design is sensitive to small voltages variations, The a selector switch can be added to the solenoid across the range of the resistances or transformer winding to gradually step the output voltage up and down, or to rotate the position of a moving transistoirsed AC regulator. When the input supply voltage Vin increases the output voltage Vload also increases.

Two components have been added, Tr3 and R5. That wraps up our discussion on transistors.

Tr2 conducts less transistorissd the current through R3 falls, reducing the p. Discrete Transistor Series Voltage Regulator. This makes them ideal for use in voltage regulator circuits where this kind of predictability is required.


Transistor-Zener Diode Regulator Circuits

The circuit consists of an N-P-N transistor and a zener diode. The bipolar transistor acts as a valve, resting within the main path of current flow. The emitter voltage of Tr1 will be typically about 0.

That is, it controls the flow of electric current traveling from the collector to the emitter, as well as the voltage available at the emitter. The working explained above happens in reverse if the supply voltage decreases. Thus, the output voltage will remain constant and will be the difference of the supply voltage and the voltage drop in the series resistance.

It basically steps down the input voltage to the desired level and keeps that in that same level during the supply. You may also like: This causes the input current to increase slightly and thus compensates for the decrease in the load resistance Rload. If Rs is too large regulato we lack the minimum current Iz to maintain voltage regulation. Your email address will not be published.

Where regulated supplies are used, the DC input voltage to the regulator is often considerably higher transistorisev the required output voltage.

Power Supplies Tutorials Voltage Regulators. This diode has its cathode held at 0V by R8, and VR2 is adjusted so that D1 is just out of conduction, i. With this simple circuit however, regulation is not perfect, and variations in output do occur for the following reasons.

The following is for information purposes only and comes with no warranty. The load current Iload of the circuit will be the maximum emitter current that the transistor can pass. This will enable us to see how placing R Limiting on the branch, rather than along the main current path, results in a major advantage over using the Zener diode voltage regulator alone.


The output of the rectifier that is filtered is then given to the input terminals and regulated output voltage Vload is obtained across the load resistor Rload.

The limiting resistor, R Limitingis located on a branch of the circuit leading to the Zener diode and the transistor base.

Module 2.2

Technology Remaking the World. This closes the mechanical switch and allows the power to flow. For this reason it is common to find over voltage protection included in stabilised supplies. If the output voltage reduces, the shunt current reduces and thus produces more load current and maintains a regulated constant output voltage.

They are explained below. When the voltage increases, the current strengthen the magnetic field, so the core is attracted towards the solenoid. The circuit shown in Fig.

Transistor Series Voltage Regulator | Engineering Expert Witness Blog

The voltage V 2 provided by the potential divider R 1 -R 2 must be equal to the sum of the base-emitter voltage of transistor Q 2 and the Zener diode. Previous post Next post. Total resistance of this circuit is said to transistorisex R Total.