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I'm attempting to represent the following fritzing diagram* as a schematic (using circuitlab).

*from https://learn.adafruit.com/ir-sensor/testing-an-ir-sensor

IR sensor - fritzing diagram

Here's my representation of the circuit using a custom part in CircuitLab.

schematic

simulate this circuit – Schematic created using CircuitLab

Does that circuit properly represent the fritzing diagram?

Also, since the IR Sensor pin 1 is pulled low when the sensor detects infrared light, does that simply mean that internally it gets "connected" to ground?

Can you explain what "pulled low" means, if it means something else than "connected to ground"?

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    \$\begingroup\$ Couldn't you have switched to schematic view in Fritzing and arranged the parts there? \$\endgroup\$ – Ignacio Vazquez-Abrams Nov 16 '17 at 22:02
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    \$\begingroup\$ Using a regulator symbol in place of the IR sensor is really confusing here, you should edit your schematic to include something that has VCC, VOUT, GND as the IR sensor has (use Custom Part in CircuitLab). As it stands, it doesn't look to be equivalent. \$\endgroup\$ – Ron Beyer Nov 16 '17 at 22:13
  • \$\begingroup\$ @IgnacioVazquez-Abrams I don't actually have the fritzing diagram but just the image of it. Also, Fritzing schematics are not pretty at all. CircuitLab is so much nicer really. But, point well-taken. Thanks. \$\endgroup\$ – raddevus Nov 16 '17 at 22:16
  • \$\begingroup\$ @RonBeyer I will look into the custom part idea. I wasn't sure how to do that in circuitlab at all. \$\endgroup\$ – raddevus Nov 16 '17 at 22:16
  • \$\begingroup\$ All of the components in CircuitLab can be rotated (R), flipped horizontally (H) or vertically (V). Oddly enough the text in the voltage regulator symbols flips too so they're best left in the original orientation. \$\endgroup\$ – Transistor Nov 16 '17 at 22:46
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enter image description here

Figure 1. The internal circuit of the TSOP382xx.

Also, since the IR Sensor pin 1 is pulled low when the sensor detects infrared light, does that simply mean that internally it gets "connected" to ground?

The 30k resistor "pulls-up" the output towards the positive supply when the output transistor is off. When the transistor turns on it offers a low resistance path between 1 and 2 ground. Your understanding is correct.

Does that circuit properly represent the fritzing diagram?

Yes, but we can make it a little clearer.

schematic

simulate this circuit – Schematic created using CircuitLab

Figure 2. Redrawn schematic using the CircuitLab 'Custom Component'.

Notice that convention is to make the circuit read from left to right with current flow from top ('high' potential) to bottom ('low' potential). Even without the internal diagram of the TSOP device the experienced circuit reader would intuitively understand that the only way for the LED to light would be if the TSOP connected the LED cathode to ground.

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  • \$\begingroup\$ Thanks very much, you answered both questions and gave me the circuitLab example that I needed. \$\endgroup\$ – raddevus Nov 16 '17 at 22:19
  • \$\begingroup\$ I meant to add, but forgot, that the circuit won't work as a basic infrared detector. The output will only turn on when it receives pulse modulated signales from an IR remote at the right frequency. See the datasheet. \$\endgroup\$ – Transistor Nov 16 '17 at 22:44

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