bjt

Hello everyone, I have a question that I haven’t been able to resolve through LTSpice manuals or Linear Technology / Analog Devices documents. When I use BJT models like Gummel-Poon, VBIC, or HiCUM, the simulator provides various parameters (IS, BF, BR, VAF, etc.), but I couldn’t find a...

You are provided with a 230 V / 50 Hz ac supply, a 6-0-6 centre-tapped transformer and a BJT of dc current gain 150. Biasing the transistor using a supply of 5.6 V (develop your own), (i) design an amplifier of voltage gain 200; (ii) If this amplifier were to drive a load of 75 Ω, what will...

You are provided with a 230 V / 50 Hz ac supply, a 6-0-6 centre-tapped transformer and a BJT of dc current gain 150. Biasing the transistor using a supply of 5.6 V (develop your own), (i) design an amplifier of voltage gain 200 i have designed could anyone correct me design as follows Av=200...

Hello, I have a circuit for which I have both a simulation and a Mathcad calculation. The circuit is designed so that the output signal (UFB_Diag) should be low (<50 mV) when the input voltage EX_in is greater than or equal to 9 V. Currently, I rely on simulation to estimate the voltage drop...

Could someone please help design a cascode amplifier with these parameters? Frequency range: 200 kHz to 20 MHz Input signal voltage: 10 mV to 1 V Power supply voltage: 5 V to 12 V Power consumption: up to 100 W And if possible, please also include the calculations showing how to achieve this...

Hi folks, Since I wanted to revise the basic configuration of BJT, I read this chapter from Purdue University based on the Book of Sedra (https://engineering.purdue.edu/wcchew/ece255s18/ece%20255%20s18%20latex%20pdf%20files/ece255Lecture_13_Feb27_BJT_Basic_Config.pdf) at page 13 where he wrote...

I'm designing a simple amplifier for educational purposes. Please ignore that this amplifier is very sensitive to changes in the transistor's DC current gain. I calculated some component values, then simulated the circuit and realized my calculations were way off. Could you help me identify...

First Time poster! I am designing a heater circuit that will source a large amount of current (5A max) to a grid of resistors (each resistor gets 5A) from multiple voltage sources so that I can change the thermal "image". I am toying around with ways to get this done. By far the easiest is to...

I'm trying to design a analog square root sub circuit to process an input voltage and output sqrt(vin). I want to Use something other than a log and antilog amplifier with a voltage divider in between but I'm really struggling to design an alternative as I am still learning. I have tried a...

Hello, I have a npn transitor configured as a switch 0v to 5v gpio pin with base resitor 2k and a 50k pull down resitor in a volatge divider configuration. I wanted to know if this pull down resitor will be okay with Ic current about 20-30ma or I need to decrease it more as the rule of thumb 10x...

Hi, I don't know exactly on designing H-bridge motor driver using BJT. I have no idea in selecting BJT's for required specification and selecting current limiting resistor values. Is it required to use zener diode as a protection to the circuit? Kindly guide me. Thanks & regards Guru

Here’s the information I know now: The comparator I’m going to use is MAX40025. The output impedance of the common base amplifier is 300ohm(Rc), the input capacitance of the chip is 2pF. I would like to transfer a fast signal to the comparator(over 45MHz). What should I consider when connect...

Hi, I have built a high side switching circuit using a PNP BJT driven by an NPN BJT. The design intent is to switch 30 VDC (supplied by a boost converter) at 1-10 kHz using a 5V Arduino signal. My rise times at 10 kHz look very good, but the fall times are slow. What is causing this? How can I...

I have been doing a school project in which I need to figure out the working principle of an existing BJT circuit, and then design a corresponding CMOS circuit of the same function and similar performance. Sort of like converting BJT technology circuits to CMOS circuits. In this picture there's...

Hi all, For a project I need to build a capacitor amplifier, with current boosting, so that rather large currents can flow without the OPAMPS saturating, as the resistance of the circuit is rather low normally, around a few Ohms. The measuring circuit is the following: The R13 resistor is in...

How to achieve an almost constant value of VBE through spice model? What does the VJE parameter do?

I simulated ( Multisim ) circuit and checked transistor model I found that in transistors model's description. I noticed BF in description what is it? Is it beta ? If it's same with beta why in model BF is constant when beta not constant? For example : .MODEL 2N2222_Multisim npn +IS=1.87573e-15...

Both of this graph show mosfet and but in switching mode As i look at the graph below I notice for mosfet the drain source amplitude is higher than the gate voltage amplitude . However , bjt , collector voltage amplitude is only reach at the same amplitude of base voltage amplitude. From this...

I had been trying to create a BJT Multistage Amplifier circuit which had a total voltage gain of -40. The problem is whenever I tried to calculate the value starting from the total voltage gain it always goes wrong and totally different comparing the simulations and calculations. Anyone can help...

Hello, I have a question regarding operational amplifiers. Whenever I search for some datasheets of high gain and high-speed Op Amps ( BW higher than 50MHz), I mostly find that they are made of bipolar transistors rather than mosfet. Why is it so? I've done some research and I've found that...