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Depletion-load processes replace this transistor with a depletion-mode NMOS at a constant gate bias, with the gate tied directly to the source. This alternative type of transistor acts as a current source until the output approaches 1, then acts as a resistor. The result is a faster 0 to 1 transition.
A typical use of these transistors is as a switch for moderate voltages and currents, including as drivers for small lamps, motors, and relays. [1] In switching circuits, these FETs can be used much like bipolar junction transistors, but have some advantages: high input impedance of the insulated gate means almost no gate current is required
The pull-down resistor R 1 biases the transistor to the appropriate on-off threshold. The output is inverted since the collector-emitter voltage of transistor Q 1 is taken as output, and is high when the inputs are low. Thus, the analog resistive network and the analog transistor stage perform the logic function NOR. [3]
The bipolar junction transistor, the first type of transistor to be mass-produced, is a combination of two junction diodes and is formed of either a thin layer of p-type semiconductor sandwiched between two n-type semiconductors (an n–p–n transistor), or a thin layer of n-type semiconductor sandwiched between two p-type semiconductors (a p ...
Bipolar transistors, and particularly power transistors, have long base-storage times when they are driven into saturation; the base storage limits turn-off time in switching applications. A Baker clamp can prevent the transistor from heavily saturating, which reduces the amount of charge stored in the base and thus improves switching time.
On-state V CA drops to around 2 V, which is compatible with Transistor–transistor logic (TTL) and CMOS logic gates with 5 V power supply. [40] Low-voltage CMOS (e.g. 3.3 V or 1.8 V logic) requires level conversion with a resistive voltage divider , [ 40 ] or replacing the TL431 with a low-voltage alternative like the TLV431.
If the gate voltage is below the threshold voltage (left figure), the "enhancement-mode" transistor is turned off and ideally there is no current from the drain to the source of the transistor. In fact, there is a current even for gate biases below the threshold ( subthreshold leakage ) current, although it is small and varies exponentially ...
The first paper dealing with avalanche transistors was Ebers & Miller (1955).The paper describes how to use alloy-junction transistors in the avalanche breakdown region in order to overcome speed and breakdown voltage limitations which affected the first models of such kind of transistor when used in earlier computer digital circuits.
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