Transformer 230/12V and buzzer

[BradtheRad]

A lot of things will become clear once you start working with real components.

You can't expect to understand ahead of time.

Hook up your meter directly to the transformer and see what it reads. Compare that to what it reads after the diode bridge. After the voltage regulator. Etc.

Hook up your meter to the photodetector and see how much it conducts in the dark. In the light. Etc.

Do not let overmuch current go through any component. Start with a resistor inline. You can reduce its value step by step.

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A lot of things will become clear once you start working with real components.

You can't expect to understand ahead of time.

Hook up your meter directly to the transformer and see what it reads. Compare that to what it reads after the diode bridge. After the voltage regulator. Etc.

Hook up your meter to the photodetector and see how much it conducts in the dark. In the light. Etc.

Do not let overmuch current go through any component. Start with a resistor inline. You can reduce its value step by step.

 

[kokosz]

Thanks, I 've bought multimetr.
Can I change Buzzer 12V 30mA to 5V 30mA with a source 9V of resistor 135Ohms ?

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But my main question is about fotoresistors : Can i buy fotoresistor which after break light beam have very small resisience ? All of fotoresistors in shops make it conversely

 

[BradtheRad]

Thanks, I 've bought multimetr.
Can I change Buzzer 12V 30mA to 5V 30mA with a source 9V of resistor 135Ohms ?

If the buzzer is rated 5V @ 30mA, then you can use it with a 9V supply by putting a 120 or 150 ohm resistor in line.

But my main question is about fotoresistors : Can i buy fotoresistor which after break light beam have very small resisience ? All of fotoresistors in shops make it conversely

You can use a transistor to turn on the buzzer, in response to your photodetector going dark.

 

[kokosz]

If the buzzer is rated 5V @ 30mA, then you can use it with a 9V supply by putting a 120 or 150 ohm resistor in line.



You can use a transistor to turn on the buzzer, in response to your photodetector going dark.

Can you make a schematic how to connect buzzer and transistor with photodetector ?

 

[BradtheRad]

Can you make a schematic how to connect buzzer and transistor with photodetector ?

 

[kokosz]

Why I need potentiometer ?

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How intensivity I will have from this transformer, becouse max of colector in transistor is 100mA

 

[kokosz]

And why in the base of transistor is a resistor 2,2k ?

 

[BradtheRad]

Why I need potentiometer ?

To adjust when the transistor turns on and off, based on how much light is on the photodetector.

How intensivity I will have from this transformer, becouse max of colector in transistor is 100mA

Your transformer (as described in your first post), will produce adequate power.

And why in the base of transistor is a resistor 2,2k ?

To protect the base from overmuch current in case you turn the potentiometer to an extreme.

The 2200 ohms could be in line with the potentiometer instead. That way the photodetector gets protected as well.

If you find that the 2200 restricts current too much, then use a lower value.

 

[kokosz]

Thanks for all i will make schematic and send soon.

 

[kokosz]

I want to connect to your schematic my set oscilator with timer 555, what i should do?

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I want to connect to your schematic my set oscilator with timer 555, what i should do?

 

[thebadtall]

this is probably what you need.

Its an adjustable voltage regulator, wich supplies regulated voltage from 1.25 to 13v just adjust the 3k pot.
as about the led, you can connect wherever you want with 1k resistor



oops - I replied for 1st page ! didnt notice it was 3 pages !

 

[kokosz]

thanks, but i want to make constant 12V DC, not regulating

 

[thebadtall]

if you adjust the value of pot. it it will be constant 12v DC

 

[kokosz]

Can i make something like this ?

 

[thebadtall]

i have never used 555 so i cannot answer, but you could use express pcb/ express sch to make schematics very quick !

**broken link removed**

 

[kokosz]

I do not command you help me with timer 555, becouse this set is good, but i' m only asking you, can I connect remainder elements ( fotodecoder, transistor ) to timer 555 (I will add that, to timer 555 + goes to 4 and 8 and GND to 1).
Thanks for program

 

[kokosz]

Does my system will work?

 

[D.A.(Tony)Stewart]

the buzzer driver is a bit fuzzy.. is this for a doorbell?

 

[kokosz]

In my schematic isn' t any buzzer, becouse i don' t know where i should connect it, and it does my system will work?
I have 12V 30mA buzzer and i want connect multioscilator ( 2 diodes ) with buzzer to timer 555.
What i must do to run my set?

 

[D.A.(Tony)Stewart]

define your buzzer properties better?
inductive? resistive? piezo? with clock or not

part number?