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Topic: Circuit Symbol (Read 380 times) previous topic - next topic

DucksandCo

Jun 14, 2019, 12:37 am Last Edit: Jun 14, 2019, 01:01 am by DucksandCo
Hello all,

I am currently making a sprinkler system that waters its plants when the soil is dry enough. My teacher has drew in this diagram regarding how I should hook up my transistor. I dont really know what symbol this really is.

http://Resistor https://imgur.com/gallery/qd8FBSI


This is the actual arduino setup.

http://Ard
https://imgur.com/gallery/YCkygPm


Thank you.

dl324

#1
Jun 14, 2019, 12:56 am Last Edit: Jun 14, 2019, 01:10 am by dl324
I am currently making a sprinkler system that waters its plants when the soil is dry enough. My teacher has drew in this diagram regarding how I should hook up my transistor. I dont really know what symbol this really is.



This is the actual arduino setup.

I've found posting pictures on this forum to be somewhat cumbersome.  I see what appears to be two images, but nothing is visible.

EDIT: fiddling with images...


No clue what your teacher is referring to.  We need to know the part number because there are three different pinouts for TO-92 transistors (2N, BC, and 2S).  Since one pin in grounded, I'm guessing it's an NPN transistor with the emitter grounded.

Southpark

#2
Jun 14, 2019, 02:05 am Last Edit: Jun 14, 2019, 02:07 am by Southpark
My teacher has drew in this diagram regarding how I should hook up my transistor. I dont really know what symbol this really is.
https://imgur.com/gallery/qd8FBSI
Adequate information is required in order to make sense of a circuit diagram. In this case --- not enough information. Device details (eg. transistor model etc) is needed. Also - intended purpose --- ie. what is required for it to do --- should be understood in advance as well.

In this case, there's not enough details. More details are required.

larryd

Boy oh boy, looks like - GND to Emitter, + to maybe a solenoid then maybe the Collector, Dout from an Arduino to the Base.



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dl324

#4
Jun 14, 2019, 03:37 am Last Edit: Jun 14, 2019, 03:40 am by dl324 Reason: Jumping through hoops to add images.
After looking at your second picture, I could see that you're using a transistor in TO-220.

This is the pinout:

Your teacher should have drawn the schematic this way:

Southpark

#5
Jun 14, 2019, 07:18 am Last Edit: Jun 14, 2019, 07:18 am by Southpark
Could it be a logic level mosfet too?

larryd

Forgot to include a kickback diode.

:(







No technical PMs.
If you are asked a question, please respond with an answer.
If you are asked for more information, please supply it.
If you need clarification, ask for help.

Paul__B

Oh dear, pictures (clickable)!






dl324

Forgot to include a kickback diode.
If your response was regarding my post, I redrew what the teacher drew, not what it should have been.

dl324

Could it be a logic level mosfet too?
The resistor on the lead marked Dout wouldn't be necessary and a resistor from gate to source would have been included so the gate wouldn't float when the GPIO port wasn't active.

larryd

If your response was regarding my post, I redrew what the teacher drew, not what it should have been.
No, I was looking at the teachers image.


No technical PMs.
If you are asked a question, please respond with an answer.
If you are asked for more information, please supply it.
If you need clarification, ask for help.

Southpark

#11
Jun 14, 2019, 11:43 pm Last Edit: Jun 15, 2019, 12:03 am by Southpark
The resistor on the lead marked Dout wouldn't be necessary and a resistor from gate to source would have been included so the gate wouldn't float when the GPIO port wasn't active.
This is all based on assumptions, which is why it can be a time-wasting exercise if there's inadequate details to begin with.

Additionally, if you assume a BJT, then the input could become floating under those conditions you mentioned too maybe, right?

Also ----- using series resistor for gates of mosfets is not uncommon.

It may well be a BJT. And all I'm saying is - if there's not enough information to start with - then it's like a goose chase.

Southpark

#12
Jun 15, 2019, 11:10 am Last Edit: Jun 15, 2019, 12:03 pm by Southpark
Make sure your breadboard connections are correct too. Example..... hole j1 has an orange wire..... but the purpose of it is unclear. Same for hole c1.

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