Category Archives: Science

Interlude #18: Measuring Forward Voltage of LEDs of Various Colours | In The Lab With Jay Jay

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This post is part of my video blog and you can find more information about this video.

Silly Job Title: …

In this video we use our Peak Electronic Design Atlas DCA75 Pro Semiconductor Analyzer to measure the forward voltage of ten different LEDs which I keep in stock.

In the following table the values are computed for VS = 5V and I = 20mA.

Size Colour VF VR RS
10mm RED 1.890 3.110 156
10mm GREEN 2.030 2.970 149
10mm BLUE 2.643 2.357 118
10mm YELLOW 1.939 3.061 153
10mm WHITE 2.615 2.385 119
5mm RED 1.889 3.111 156
5mm GREEN 1.995 3.005 150
5mm BLUE 2.710 2.290 115
5mm YELLOW 2.019 2.981 149
5mm WHITE 2.775 2.225 111
VS
Supply voltage, e.g. 5 V.
I
Desired LED current in milliamps, e.g. 20 mA.
VF
Forward voltage, as measured; e.g. 1.8 V.
VR
Voltage across resistor = VS – VF.
RS
Series resistance to use, in Ohms = VR / I.

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Learning the Art of Electronics: 1L.4.1 Internal resistance of the movement | In The Lab

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Silly Job Title: Tech Lead. I am the Tech Lead!

In this video we continue to work our way through Learning the Art of Electronics. In this video we continue with 1L Lab: DC Circuits and measure the internal resistance of our meter movement.

We use the METCAL PS-900 Soldering Station for soldering.

We use the Pro’sKit SS-331H Desoldering Pump to desolder (unsuccessfully).

We use the Riden RD6006 Bench Power Supply to provide 1V power for testing.

We use the Fluke 17B+ Digital Multimeter to measure current/voltage/resistance.

We use the EEVblog BM2257 Digital Multimeter to measure current/voltage/resistance.

We use the Brother P-Touch D210 Label Maker to label our circuit.

We use the Sharp EL-546L Scientific Calculator to calculate our values.

We use the ElectroCookie PCB Prototype Solderable Breadboard to make our circuit on.

We use the Multicomp Pro MP701033 Resistor Decade Box to provide test resistances.

We use the WilliamKlein Music Stand to hold our textbook.

We use the Carpenter Mechanical Pencil to take notes.

We use the Hakko CHP 3C-SA Precision Tweezers for tweezering.

We use the Plato Model 170 Wire Cutter to cut wires and trim leads.

We use the Kaisi S-160 45x30cm Repair Mat as our workspace.

The circuit I make in this video for interfacing the meter movement is JJ001:

Photo of circuit JJ001

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Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

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The Transistor and “Amplification” | Project 6/30 | Maxitronix 30in1 | In The Lab With Jay Jay

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Silly Job Title: Switch Sleuth. I am the Switch Sleuth!

In this video we continue to work through our Maxitronix 30in1, today doing project #6: The Transistor and “Amplification”. In this project we see how an NPN transistor acts as an amplifier.

The HFR trigger coupling I use at the end of the video is called High Frequency Reject, it hides high frequency components from the triggering system and in this case fixed our triggering issue. I haven’t used HFR trigger coupling before. The Rigol user manual for the MSO5000 series doesn’t explain the feature, it just says: “HFR: rejects the high frequency components”.

We use the Rigol MSO5074 Mixed Signal Oscilloscope to examine our input and output voltages, and also to provide a test sine wave for input.

We use the UNI-T UTi260B Thermal Imager to look at the thermals, but there wasn’t anything really to see.

We use the UNI-T UTG962E Signal Generator to provide an input signal, but we couldn’t get it to work properly so we used the signal generate from the scope instead.

We use the Kaisi S-160 45x30cm Repair Mat as our workspace.

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

3ELIGHTING 10″-26″ VESA Wall MountThis is an image of the product.

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Learning the Art of Electronics: 1L.3 Voltage divider | Learning Electronics In The Lab With Jay Jay

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Silly Job Title: Note Taker. I am the Note Taker!

In this video we continue to work our way through Learning the Art of Electronics. In this video we continue with 1L Lab: DC Circuits and make a voltage divider.

We use the METCAL PS-900 Soldering Station for soldering.

We use the Riden RD6006 Bench Power Supply for 15V power.

We use the Fluke 17B+ Digital Multimeter to measure voltage and resistance.

We use the EEVblog BM2257 Digital Multimeter to measure voltage and current.

We use the Brother P-Touch D210 Label Maker to label our circuit.

We use the ElectroCookie PCB Prototype Solderable Breadboard to make our circuit on.

We use the Multicomp Pro MP701033 Resistor Decade Box for variable resistance.

We use the WilliamKlein Music Stand to hold our textbook.

We use the Scotch Titanium Scissors to cut, cut, cut.

We use the Carpenter Mechanical Pencil to make notes.

We use the Hakko CHP 3C-SA Precision Tweezers for tweezering.

We use the Plato Model 170 Wire Cutter to cut, cut, cut.

We use the Kaisi S-160 45x30cm Repair Mat as our workspace.

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

MECHANIC Hard BrushThis is an image of the product.

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Module Monday #8: HW-038 Water Level Sensor Module | Learning Electronics In The Lab With Jay Jay

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Silly Job Title: Electronics Guy. I am the Electronics Guy!

Today is Module Monday.

In this video we take a look at the 1pcs Rain Water Level Sensor Module Detection Liquid Surface Depth Height For Arduino.

The code for this Arduino sketch is here: 2025-11-24-HW-038-Water-Level.ino.

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Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Yutiars Round Paint BrushesThis is an image of the product.notes

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Module Monday #7: HW-028 Rain Drops Sensor Module | Learning Electronics In The Lab With Jay Jay

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Silly Job Title: Bench Master. I am the Bench Master!

In this video we take a look at the HW-028 Rain Drops sensor module: Separate PCB Board Raindrop Module Sensor Rising Water Level Detection Module Raindrop Sensor Board. Project doco is here: HW-028.

We found some instructions and tutorials, including these:

Also we noted the use of the LM393 comparator on the module.

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Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Galacok 12 Pcs Magnetic Phillips Screwdriver SetThis is an image of the product.

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The Transistor, an Electronic “Trigger” | Project 5/30 | Maxitronix 30in1 | In The Lab With Jay Jay

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Silly Job Title: Power Provider. I am the Power Provider!

In this video we continue to work through our Maxitronix 30in1, today doing project #5: The Transistor, an Electronic “Trigger”. In this project we see how an NPN transistor works.

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Emenne 110111 Brush HolderThis is an image of the product.

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