Author Topic: Emitter & Photo transistor  (Read 3028 times)

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Offline dsesmgTopic starter

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Emitter & Photo transistor
« on: August 28, 2009, 08:37:22 PM »
Hi, I am trying to test this photo transistor with an emitter.
The specification of the photo transistor is this.
http://www.flickr.com/photos/34955071@N02/3848158536/sizes/o/
http://www.flickr.com/photos/34955071@N02/3847368037/sizes/o/
http://www.flickr.com/photos/34955071@N02/3847368107/sizes/o/

And, the specification of the emitteris this.
http://www.flickr.com/photos/34955071@N02/3855946584/sizes/o/
http://www.flickr.com/photos/34955071@N02/3855946586/sizes/o/
http://www.flickr.com/photos/34955071@N02/3855946588/sizes/o/

I successfully got the emitter glowing. I've looked through a digital camera and I've checked a beautiful light was glowing.
The schematic for the emitter is this.
http://www.flickr.com/photos/34955071@N02/3845028272/sizes/l/
Please ignore the 1N4004 in the circuit as I've taken it out from there.

I also, got the photo transistor working. I connected a DC geared motor in the circuit and I beamed a light. The motor spins well whether I beam a light.
The shematic for the photo transistor is this.
http://www.flickr.com/photos/34955071@N02/3843611141/sizes/l/

The problem is, the transistor is not responding to the emitter at the moment.
Not at all.  :'(
Could you advise me what have I done wrong?
As you see, the operating voltage of the emitter is 1.5VDC, 60mA. So I supplied 1.5V using a variable DC adaptor(1.5~13V, 600mA). I tried to put a normal LED in the place where the emitter was.
LED is not blinking.

Offline Soeren

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Re: Emitter & Photo transistor
« Reply #1 on: August 29, 2009, 01:41:09 AM »
Hi,

The specification of [...]
Please post a link to the datasheets (instead of pictures of the pages) next time.


The problem is, the transistor is not responding to the emitter at the moment.
Not at all.  :'(
Could you advise me what have I done wrong?
The circuit ;)


As you see, the operating voltage of the emitter is 1.5VDC, 60mA. So I supplied 1.5V using a variable DC adaptor(1.5~13V, 600mA).
No. LED's are current controlled devices and the voltage drop is not what you aim for and neither is 60mA, when your datasheet says 40mA.

This circuit should help.

The LEDs have a current limiter (Q1/R2) to keep them happy on a range of voltages and the detector is used in a voltage divider which will keep that one smiling.
The TIP102 is not a good choice for the LED driver, since it hasn't got much gain on low currents.
I don't know how much current your motor takes, but the BC337 is good for a bit more than 0.5A
If it doesn't work right away, R3 and R4 should be changed a bit, but try it in 100% darkness if it seems to keep running before you make any changes.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline dsesmgTopic starter

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Re: Emitter & Photo transistor
« Reply #2 on: August 29, 2009, 05:45:15 AM »
Hi, thank you very much for showing me those great schematics.
Some componentes shown in that schematics are not available now.
So, I will get them at once and test it right away.
Thank you. Have a good day.

Quote
I don't know how much current your motor takes,
It takes max 1A at 5v when it starts, and takes 0.4A at 5v in normal rotation.
That's what the supplier says.

Offline Joker94

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Re: Emitter & Photo transistor
« Reply #3 on: August 29, 2009, 05:51:32 AM »
Some componentes shown in that schematics are not available now.
So, I will get them at once and test it right away.

What do you mean by some components shown in the shematics are not available  so i will get them at once. ???

Offline dsesmgTopic starter

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Re: Emitter & Photo transistor
« Reply #4 on: August 29, 2009, 06:56:22 AM »
Hi, I don't have BC547, BC337, BC557 right now.
So, I am going to order for those things. :)

Offline Joker94

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Re: Emitter & Photo transistor
« Reply #5 on: August 29, 2009, 07:01:14 AM »
ah, that is what you ment

Offline dsesmgTopic starter

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Re: Emitter & Photo transistor
« Reply #6 on: August 29, 2009, 08:18:50 AM »
Hi, Soeren. I have a question.
Quote
This circuit should help.

Is it ok if I put 10 emitters in this circuit?
The transistor I mentioned earlier will move above the emitter and I will arrange the number of the emitter so that the transistor(motor) could stay turned on as long as it passes over the emitters.
I think I must test first, but I assume the number of the emitters needs to be 10pcs(or a little more).

Offline Soeren

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Re: Emitter & Photo transistor
« Reply #7 on: August 30, 2009, 02:10:44 PM »
Hi,

Is it ok if I put 10 emitters in this circuit?
Sure, as long as you raise the supply voltage accordingly.
They have to connect in series of course.


The transistor I mentioned earlier will move above the emitter and I will arrange the number of the emitter so that the transistor(motor) could stay turned on as long as it passes over the emitters.
I think I must test first, but I assume the number of the emitters needs to be 10pcs(or a little more).
Didn't you see the post about the flip-flop?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline dsesmgTopic starter

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Re: Emitter & Photo transistor
« Reply #8 on: August 30, 2009, 08:04:48 PM »
oh. I am sorry . I missed the last post in that topic.