Recent content by ToonBlue

I have insert the circuit with led in it and change the resistors location. When R2 is 10 ohm , LED1 doesn't light up. When R2 is increased to about 40k ohm , LED1 light up. May I know how this circuit work? Why does the increase in R2 will lead to LED1 begin light up?

Homework Statement This is not a homework question. I am trying to learn how BJT work as a switch so I come out with circuit to understand how BJT functions as a switch. I use mulitsim by the way to try out these circuit 2. Relevant diagram The Attempt at a Solution [/B] I understand that...

May I know how do I calculate the value of R1 and R2?

Can I have some explanation why it is able to invert the signal?

The A in my diagram means that it is connected to the LED.

Homework Statement I am using the a hall effect sensor - model 480-5198-ND. I have tested this simple circuit using a LED and it is working. However, it is "ON" by default. Only when the magnet is near the hall effect sensor , it will be "OFF". How do I make it such that it is OFF by default...

my bad. This is the video link

In this video , he shows the basic of hall effect sensor. At the video 1:46 , he shows the latch effect of hall effect sensor. Does this latch comes with the hall effect sensor? What I mean is built into the chip? or he did something to it? This is not a homework or assignment question. I am...

I am not really sure which is why I am asking for some hints here. I am not asking that you help me solve my problem by giving me solution. I am asking for information on where I can begin searching for solution to my problem. for example some key term that might give me some clue to my answer

Homework Statement I want to design a circuit that is able to differentiate an sms signal and also a telephone signal. What I mean is the telephone signal is when someone calls you. Example , when someone sms you , your circuit will detect the sms signal and LED 1 will light up (use to...

Homework Statement I am only allowed to use these items for my project opamp , zener diode , led , resistor , capacitor , p or n mosfet , NPN BJT or PNP BJT , diode , temperature sensor , LDR , speaker , trimmer , switch(normal) , pusb-button switch , infra red emitter , red detector , speaker...

Homework Statement When switch A is turn on , LED 1 will light up When switch B is turn on , LED 2 will light up. When one of the LED is turn on , all other LED will not turn on. When the LED is turning on and if you are to press another switch , it will have no effect at all. what I mean is no...

May I know why does the dE point away and not toward the dL?

Homework Statement Let said I have found out the ripple output voltage for a given circuit using a simulation software and it gives me 10V + and then when I do the actual experiment , I got about 7.8V for my output ripple voltage. With a difference of more than 20% , does the reading i get...

I would like to ask one more question. Does this consider to be a linear relationship ? It doesn't look very linear to me?