ir Receiver pin outs

Hi
Bit confused about seeing different ir Receiver pin outs as below.
Spike

Hi Spike

What's confusing you ?

MM

Pin outs are different !

Have a couple in stock, no info on them , just wanted know the pin outs for a ir photocell led

OK, where did you get the little sketch ' IR Receiver Symbols ' .. I think that is incorrect ! The schematic seems right to me

MM

Hi
Thanks for your replies, just got them from google.
There is no way to check ,apart from maybe the ground to the shell ! .
Cheers
Spike

OK, two comments then .. .. .. .. my experience is that there are as many incorrect diagrams on Google, as there are correct !

.. .. .. .. .. all the IR receivers I have used have been connected the way the schematic suggests, I guess it's a matter of try one and see !

Good Luck

MM

The datasheet is always a good place to start.....

Visitor said:

The datasheet is always a good place to start.....

Click to expand...

Absolutely true, however, since the OP was unable to identify the part it there is the question of which datasheet ? Eh, What ?

MM

There are several very distinct types of IR receivers, and there is a part number given in the schematic. Perhaps that's a more effective place to start a search (comparing the piece in hand to a data sheet), than asking people who don't have any clue as to the part he has to to guess?

Using my Google Superpowers, here are two distinct and easily identifiable types of IR receivers. Chances are one of these types match, as least as far as pinout, and if not, spend another 2 minutes searching.

Or ask a stranger who can't see what you have to psychically guess.

Visitor said:

There are several very distinct types of IR receivers, and there is a part number given in the schematic. Perhaps that's a more effective place to start a search (comparing the piece in hand to a data sheet), than asking people who don't have any clue as to the part he has to to guess?

Click to expand...

ROFL ! End of .. .. ..

The one I'm currently using has the pinout in the first drawing above. I.E. Left to Right is Out, Gnd, Vcc. And the Vishay datasheet I referred to has two different pinouts. I note that in the datasheet it shows a 33k resistor to Vcc, could this be used to identify the type? The Vishay datasheet does not show the offset pin as in the above datasheet.

Mike.

The tsop1738 is obsolete. datasheet here: https://drive.google.com/file/d/17quZDUJlujMtpBa-bwOdghsv7O8pEucu/view

R5 in the circuit diagram of 47 ohms might confuse someone. It's basically a fuse. There is an 80K built in pull-up in the receiver.

The pull-up depends on what logic your interfacing too or can interface to. 80K use in the 1738 is a weak pull up. Sometimes power consumption matters. The weak pull up does provide a path for leakage current.

There's a nice blurb on Vishay concerning these devices, You have a frequency of operatio, Electronically, it's important, but a 30 kHz receiver will see a 30 kHz signal. The harmonic gets through,

The lens is important. It blocks the non-IR light,

Sunlight contains IR and so do CFL bulbs. Sunlight won;t be fount at 38 kHz and hopefully the designer of your CFL light didn't choose that frequency.

The next problem is rejection of non-carrier frequencies.

The final problem which NEC nailed really good was AGC or automatic gain control. What did NEC do? They transmit known garbage which allows the reciever to adjust it;s gain. That first frame isn't important as far as data is concerned. It's a start preamble.

It would be really hard to design a receiver from scratch. Especially one that rejects sunlight and CFL light.