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Can transistors be on or off?
In an ideal switch, the transistor should be in only one of two states: off or on. The transistor is off when there’s no bias voltage or when the bias voltage is less than 0.7 V. The switch is on when the base is saturated so that collector current can flow without restriction.
Which wire on a transistor turns it on and off?
Base
The Base (B) is the On/Off switch for the transistor. If a current is flowing to the Base, there will be a path from the Collector (C) to the Emitter (E) where current can flow (The Switch is On.) If there is no current flowing to the Base, then no current can flow from the Collector to the Emitter.
How do you make a timer circuit?
(1.1*55*1000*1000)/1000000 = 60.5 ~ 60 seconds. So to build a 5 minute timer circuit, we would be simply changing the resitor value to 272.7k ohm in above given 1 minute timer circuit. Similarly to create a 10 minute timer we would be changing the resistor value to 545.4 k ohm.
When does no current flow through a transistor?
If the base-emitter voltage is below 0.7 V, the transistor is in “cutoff” and no current flows through the emitter or through the collector. That’s it. That’s how a BJT works. The collector-emitter current flow is inherent in the construction of the transistor.
What are the basics of a transistor circuit?
Transistor basics •Emitter to base junction is forward biased (normally) •Collector to base junction is reverse biased (normally) •Transistors are current operated devices, so KCL should be applied first: –I E = I C + I B Basics continued •Leakage current: I CBO (Emitter open) –Usually is considered negligible, but can affect things when I C
What kind of circuit is a transistor delay circuit?
The transistor delay circuit may be helpful to learn some electronics basics. The circuit is pretty simple. It only contains a transistor, a capacitor, several resistors, a switch and an LED. The circuit uses an RC filter to turn an LED on with a little delay.
What is the minimum current gain of a transistor?
One of the key characteristics of the transistor is the current gain. This number describes how much the emitter current changes for a given change in the base current. The current gain varies with the amount of current flowing in the collector. For the 2N3904, the minimum current gain at 0.1 mA collector current is 40.