What would you like to do?
When we use a transistor as a switch, we will be operating it in either an "all on" or an "all off" mode. Depending on the transistor, we'll just apply some "maximum" base vol…tage to drive it into saturation and allow for maximum collector current, or we'll not apply any base voltage and the device will not be conducting any current through it. That's the "on and off" of it. This idea applies to the "standard" transistor. Things change a bit for FETs and some other devices, but the concept of using the device in an "all on" or "all off" state is common to the application of all devices acting as switches. We either turn them "all the way on" or "all the way off" via the base, gate or applicable terminal of the device.
A: When a transistor is saturated current can flow in both direction qualifying it as a switch
by creating two circuit loops
by saturating the junctions it becomes a low resistance current path from a relatively hi impedance.
A transistor used as a switch is operated in saturated mode, where the ratio of base-emitter current over collector-emitter current is far more than hFe, or beta gain. The tra…nsistor is either fully on or fully off in this mode. A transistor used as an amplifier is operated in linear mode, where the ratio of base-emitter current over collector-emitter current is equal to or less than hFe, or beta gain. The transistor is partially on in this mode, and is operating as a current controlled current sink.
A: actually any active components will oscillate with positive feedback A transistor can be used as an amplifier along with an LC tank circuit to form an oscillator; it is an …active device (as LIBURNO states) which will amplify the feedback signal coming out of the LC tank circuit. The tank circuit has a natural resonant frequency, meaning the L and C together will try to generate a specific frequency; this is then fed back into the input of the transistor amplifier, and the output is fed to the LC tank circuit exacerbating this oscillation until it reaches its' maximum level. An inverting amplifier can be used similarly; the output is fed to the input; this will cause the output to change as fast as the amplifier can. The frequency of this design is much harder to control, but potentially higher. Also, without the LC tank, the output voltage will remain lower.
pulse of positive voltage is not indicate to zero
When you turn it on, it conducts, when you turn it off it doesn't conduct. Just like a switch.
the magical computer fairies wave there magic wands and make electricity appear sometimes they live in transistors as this is where theyare happiest and that happiness is turn…ed into electricity
A transistor does not act as an amplifier. It is used as a component in an amplifier circuit.
When transformer is used in step up mode then we can use transformer as amplifire
transistor has 2 output 1 and 0 so can be used as a switch
Amplification is the process of linearly increasing the amplitude of an electrical signal. - A transistor can act as an amplifier directly using the gain, b. - Keep in mind th…at when a transistor is biased in the active (linear) region, the BE junction has a low resistance due to forward bias and the BC junction has a high resistance due to reverse bias. i) DC and AC quantities - Amplifier circuits have both ac and dc quantities. - Capital letters are used will be used for both ac and dc currents. - Subscript will be capital for dc quantities. - Subscript will be lowercase for ac quantities. ii) Transistor amplification - A transistor amplifies current because the collector current is equal to the base current multiplied by the current gain, b. - Base current (IB) is small compared to IC and IE. - Thus, IC is almost equal to IE.
"Transistor" name itself revels it transfers resistance from its input to its output (Transfer of resistance). Input resistance varies when input voltage varies, similarly out…put resistance varies and this leads to voltage variation at the output. Thus input to output voltage variation is called amplification. this is how transistor can be used as an amplifier. If input voltage is minimum output voltage becomes maximum i.e. its output resistance becomes maximum in common emitter configuration. Thus if no voltage is applied at the input its collector resistance becomes infinite or as if open circuit. Similarly if input current is increased output current increases and out put can behave as short circuit. This is how output current can be switched off or on using no input current or with minute input current. Unlike a digital device, the transistor is an analogue device which can be switch on/off to maximum or any gradient in between. Providing a small AC voltage to the base creates an amplified analogue of this signal across the emitter and collector.
All transistors are reactive to light. If you cut the top off of a regular PNP or NPN transistor and expose it to a sufficient amount of light, a current will conduct through …any two of its leads. If you want to use it as a switch that turns on when it's night, you could attach the output to an inverter and then put the transistor up against a window. I guess when it got dark, it would conduct electricity...
In a transistor, a small current in the base-emitter circuit stimulates a significantly larger current in the collector-emitter circuit by breaking down the barrier in interna…l diode junctions. External resistor networks may be used to regulate these currents and produce larger voltages from smaller ones.