Need help with Voltage/Current

[shaneshane1]

I have a IR Receiver with input(5V max) ground and output, what i dont understand is, im using a 5V regulator for the input of the IR receiver and if i use a brand new 9V battery, the output remains high no matter what, but if i use a old 9V battery of the same brand that has lost about 1.5 - 2V the output works fine(goes low when it receives a signal from a IR remote)

Does anyone know why this is happening? i tested the voltage on the regulator with a mutimeter with both batteries, and they both show 5V?

 

[vinke]

Make sure that the receiver is getting the signal cause there is no reason why it shouldnt be working.If you have a small transistor(radio, with am band), turn it on,and when you press on the remote you should hear a noise on the radio .

 

[shaneshane1]

Make sure that the receiver is getting the signal cause there is no reason why it shouldnt be working.If you have a small transistor(radio, with am band), turn it on,and when you press on the remote you should hear a noise on the radio .

I dont have a radio with am band,

when i press the tv remote there is no difference in the output what so ever( with a brand new 9V battery), but if i change the battery with a 9V battery that has lost 1 - 2 volts it works 100% ? im confused, do you think there is something wrong with my receiver?

 

[jpanhalt]

Are you using the same battery for both the IR receiver and transmitter? If so, the older battery may drop below the minimum voltage of the regulaor when transmitting. That might make it look as if the receiver was working. John

 

[shaneshane1]

no the transmitter battery is different ( it is just a tv remote )

and the receiver is set up an a bread board with a 9V battery supply, then it is regulated to 5V for the receiver.

 

[vinke]

I dont have a radio with am band,

when i press the tv remote there is no difference in the output what so ever( with a brand new 9V battery), but if i change the battery with a 9V battery that has lost 1 - 2 volts it works 100% ? im confused, do you think there is something wrong with my receiver?

If it worked with the old battery ,your receiver must be good,try to use another new 9V battery,if it doesnt work then just use your old battery.
Sometimes when things work one way better not getting ulcers thinking why it doesnt work the other way.

 

[Roff]

Do you have capacitors to ground from the input and the output of the regulator? Maybe the regulator oscillates with the new battery, but not with the old one.
Do you have a part number for the receiver? What kind of regulator are you using?

 

[shaneshane1]

Do you have capacitors to ground from the input and the output of the regulator? Maybe the regulator oscillates with the new battery, but not with the old one.
Do you have a part number for the receiver? What kind of regulator are you using?

**broken link removed**

the regulator is a 7805

and i havn't been using caps, on the input/output of the receiver.

 

[Roff]

**broken link removed**

the regulator is a 7805

and i havn't been using caps, on the input/output of the receiver.

That link is a search page. Give us a part number.
And I didn't say caps on the receiver, I said caps on the regulator. Maybe that was a typo on your part?
You need caps on the regulator, or it may oscillate. See the 7805 datasheet, if you don't have them.

 

[audioguru]

Look at the datasheet for your IR receiver and for the 7805.
The TSOP17xx IR receiver needs a 100 ohm resistor from the 5V supply then a 4.7uf capacitor to ground.

The uA7805 is spec'd with a 0.33uf input capacitor and a 0.1uF output capacitor. It is also spec'd with a minimum supply voltage of 7V to 8V.
But a 9V battery quickly drops to 7.2V which is too low for it.

I use low-dropout 5V regulators with 9V batteries. They regulate perfectly until the battery voltage is less than 5.4V.

 

[shaneshane1]

sorry i ment regulator, that page should have went to the datasheet, but didnt, if you type in the catalogue number ZD-1952 it should show up, other than that the part number on the back of it is 3867 49A

il try those caps now.