# transistor

1. ### Transistor as an amplifier

I'm currently working on this circuit and I run upon this question which I'm not sure I understood it correctly : For starters I have these values below - UCE=5V R1=6.1kΩ R2=1.35kΩ RE=1kΩ R3=1.5kΩ V1=15V IC=2mA UBE=0.4V B=180 Given formula rBE≈40mV / IB First I calculated CE with the use...
2. ### IRF540N application as a switch trouble

I am fairly new to using MOSFET's in circuits and I am a little stuck. I want to use the IRF540N as a switch, which will receive a voltage to the gate, and 18-30 volts at the drain. I would like for the source to essentially follow the voltage of the drain as long as there is voltage being...
3. ### I made my first amplifier!

We kinda learned about this circuit in the electronics 1 lab, but I don't understand everything, i have some questions and unfortunatly my lab professor is quite a Karen and won't even hear my questions... Anyway, these are my questions: 1) Which elements can I mess with to increase the volume...
4. ### manage 12V pulse and 5V pulse on the same pin

I have Atmel controller which requires a 12V pulse and 5V pulse during flashing. I have a 12V supply and derived 5V from it using a regulator. But I want to know how can I give the 12V pulse and 5V pulse on the same pin. We can manage to give pulse single voltage level using NPN transistor but...
5. ### How Did This Circuit Go So Wrong?

I built this circuit based on the examples in the datasheet. It worked. Transistor Q3_1 is BUJ100LR,412Bipolar Transistors - BJT Bipolar Transistors - BJT Trans GP BJT NPN 400V 1A 3-Pin https://www.mouser.ie/datasheet/2/848/BUJ100LR-1846655.pdf C2_1 is 4.7uF Tantalum Capacitors 20V...
6. ### wiring an arducam with the power line on a transistor

I've set up an arducam mini 2MP plus with a nrf52DK (similar to an arduino for this set up) to take pictures. Ive got the board and camera working when the camera is wired with the VCC line and GND wired directly into the boards 3.3v line and ground pins. The arducam uses about 100 mAmps when...
7. ### How to calclate Rb and Rc value for NPN transistor?

Here is a part of my schematic. K pin from LCD is connected to NPN transistor. A pin is connected to Rc and Vcc, 5V. Base is connected to uController. It is Atmega16. 5V supply. I am using 2N3904 transistor as it is showed at the picture. Electrical Characteristics form datasheet: Vcbo= 60V...
8. ### Transistor heating problem in slayer exciter circuit

i made this project but it is not working and the transistor is heating up very fast, i couldn't find anything regarding this specific project but as far as i understood i should maybe use another transistor, what do you suggest?
9. ### Current limiting circuit

Hai Friends. The above given is a current limiting circuit one I found from google. https://electronics.stackexchange.com/questions/200716/current-limiting-with-mosfet Can anyone explain how the circuit works?.
10. ### How to design a BJT Tansistor Amplifier with voltage divider biasing

I'm not sure if this has been posted somewhere before, but I can't find anything that really addresses this type of a problem. For college we need to design an amplifier circuit using a transistor, this is not that bad. The problem is that there is no proper explanation that I can find of where...
11. ### Do we select a large or small BJT to amplify high frequency response?

Part of me thinks we need a smaller BJT, to reduce base emitter junction area. but I am confused
12. ### I need help with my circuit (optocoupler, transistor, relay)

Hello, i've got a newbie question, i hope some of you more experienced guys can give me an answer. I've recreated a simple circuit, that closes relay contacts using optocoupler and transistor, just for fun and i've found out that it's not working, after some time i've succeded to get the circuit...
13. ### DC biasing, headroom, clipping in MOSFET amplifiers

Okay so my question relates to biasing and threshold voltage in a MOSFET amplifier. So in an amplifier the clipping occurs when the signal hits the power rails according to all the reading I’ve done. That’s how much voltage swing you supposedly have before clipping. So if you have an 18 volt...
14. ### continuity tester

Hi all I need to develop a continuity tester, i need to check a connector simply continuity between two ends of the connector using an arduino, using an transistor too but unable to find a circuit for it. How to connect transistor with arduino to make a project
15. ### Identify the Maximum Voltage that can be applied across Zener, MOSFET and Transistor

In many Zener Diode datasheets, I have witnessed that in the Absolute Maximum Ratings section, they don't include the "Maximum Voltage" that can be applied to the Zener diode. If the applied voltage crosses the Zener breakdown voltage, then the voltage will start to conduct and will enter in the...
16. ### NPN BJT Emitter Follower - supply at Collector Current (Ic).?

Greetings everyone, I am planning to design a current amplifier using an NPN BJT Transistor with an Emitter Follower configuration. On top of that, instead of using batteries, I am using 2 separate LDO voltage outputs as the input voltage(Vin/Vbb) to the BJT as well as the supply voltage...
17. ### SMD Transistor Identification

Hello, I need some assistance identifying this smd component on an LCD inverter. It is marked DK and then QM right below it. I have another identical board which is a newer revision and the same part is marked DK however with QS below it. My preliminary research on s-manuals seems to indicate...
18. ### Arduino Motor Circuit Only Getting Less Than 1V

Hello, I have built this motor circuit for my Arduino and when running it only gets less 1v and the motor spins very slowly and my bigger motor doesn't spin at all. I have attached the diagram that I followed below. The Motor should be getting 5v from the Arduino although something seems to be...

20. ### Slayer Exciter using darlington pair

Hi guys, this is my first post here. I hope I'm in the right section. I've made a slayer exciter with a 22kohm resistor, a 2n2222 transistor, using a 9v battery. My secondary is 0.25 mm and 10 cm in lenght. My primary is 4 turns. I wanted to obtain some sparks, and I added a 47k instead of 22k...