To turn on an NPN transistor, a voltage is applied across the base and emitter terminals. This causes electrons in the Base wire to move away from the transistor itself and flow out towards the power supply. This in turn yanks electrons out of the P-type base region, leaving 'holes' beh...
Look atFigure 1. It shows a typical general-purpose (NPN) transistor/LED circuit. If you hook up +5 volts to Vcc in this circuit and pulse the input terminal (Vin) with +5V, 0V, +5V, etc., the LED will flash on and off accordingly. Of course, in order to make this circuit fu...
An ordinary NPN transistor will turn ON when the base voltage is about 0.65v more than the emitter but a MOSFET needs the gate terminal to be at least 2v to 5v, (depending on the type of MOSFET) above the source voltage. This is called theGATE VOLTAGEand the exact value is difficulty...
The transistor works like an electronic switch. It can turn a current ON and OFF. A simple way to think about it is to look at the transistor asa relaywithout any moving parts. A transistor is similar to a relay in the sense that you can use it to turn something ON and OFF. But a...
not required. It is included to ensure that the transistor base is never fully grounded, and thus it is never completely disabled or shut off. It also ensures that the current through the LDR can never exceed a certain minimum limit, no matter how bright the light intensity is on the LDR...
In this article, we will show how to connect a transistor in a circuit so that it acts as a switch to turn on or off a load.
Figure 4. Basic NPN Transistor Switching Circuit. Image used courtesy of Simon Munyua Mugo The circuit is similar to that of the Common Emitter circuit. The difference is that we need to turn the transistor fully ON (saturated) or fully OFF (cut-off) to be able to operate it as a swit...
NPN transistor on the left, PNP on the right. A positive Base voltage on an NPN transistor will allow current to flow through the resistor. A negative Base voltage on a PNP transistor will allow current to flow. Here's two transistor circuits that look and function very much like tube amp...
region” or “ON mode” when using a bipolar NPN transistor as a switch as being, both the junctions are forward biased, IC = Maximum, and VB > 0.7v. For a PNP transistor, the Emitter potential must be +ve with respect to the Base. This is theworking of the transistor as a switch...
One 7CT1N will test a PNP and while it is in place the second 7CT1N can be used to select a transistor that is closely matching as pair. There are two curves worth paying attention when comparing two complementary transistors. The first Step in the curve closer to zero should be ...