Learning the Art of Electronics: Constant Current BJT Circuit from AoE | 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 working through Learning the Art of Electronics. Today we don’t do any course work, rather we do two exercises from the text, AoE ex 2.9 and 2.10 on page 86, and make a BJT-based current source as described in AoE Figure 2.32 on page 87.

These are the results I got as I varied the load resistance:

RL Ω VL V IL µA VBE V
1 0.06 0.0 -0.746
10 0.18 0.0 -0.745
100 1.21 0.0 -0.740
1k 5.41 0.0 -0.699
10k 7.54 4.9 1.145
100k 7.79 4.8 1.598
1M 7.88 4.9 1.637
10M 7.96 5.0 1.641

My notes are here:
John's notes for AoE ex-2.9
John's notes for AoE ex-2.10
John's notes for the circuit in AoE figure 2.32 A

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

We use the AiXun H314 Hot Air Gun for heat shrink.

We use the MUIN Solder Fume Extractor for fume extraction.

We use the Riden RD6006 Bench Power Supply for 10 V power input.

We use the EEVblog BM2257 Digital Multimeter to take measurements.

We use the Fluke 17B+ Digital Multimeter to take measurements.

We use the Peak Electronic Design Atlas DCA75 Pro Semiconductor Analyzer to check our NPN transistor pin out.

We use the Sharp EL-546L Scientific Calculator to crunch some numbers.

We use the ElectroCookie PCB Prototype Solderable Breadboard to build our circuits on.

We use the Multicomp Pro MP701033 Resistor Decade Box as a variable load resistor.

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

We use the Plato Model 170 Wire Cutter to trim component leads.

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! :)

p.s. today I added AoE to my spell check.


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!

Yum Cha Stainless Steel SpudgerThis is an image of the product.

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Unboxing #35: Unboxing the HP Prime CAS Graphing Calculator | 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: Spark Specialist. I am the Spark Specialist!

In this video we unbox our HP Prime graphing calculator.

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 UV Curing LightThis is an image of the product.notes

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Mail Call #62: Loot from AliExpress, Amazon, and eBay | 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: Phase Phaser. I am the Phase Phaser!

In this video we take a look at what arrived in the mail:

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

p.s. today I added BNC, BNC-SMA, Xylitol, html, Thermocouple, CAS, LCR, Brushless, IGBT, Triode, PWM, LiPo, LiFe/em>, NiMH, and NiCd to my spell check.


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!

Yum Cha Half Round Nose and Half Groove PliersThis is an image of the product.

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CH341A Programmer

Today I watched You Need This $10 Flash Programmer, But It Needs This Fix Before You Use It! and I picked up a few from AliExpress:

The video references thingino.com, which has firmware for cameras with Ingenic SoC.

Learning the Art of Electronics: Constant Current Reading from AoE and AoEx | In The Lab

You can support this channel: patreon.com/JohnElliotV

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

Silly Job Title: Connector Kingpin. I am the Connector Kingpin!

In this video we continue working through Learning the Art of Electronics. Today we don’t do any course work, rather we do selected readings about current sources found in the text.

Our reading from The Art of Electronics 3ed includes:

  • §2.2.6 pg 85-87 RE: resistor and BJT current sources
  • §4.2.5 pg 228-230 RE: op-amp current sources
  • §9.3.14 pg 620-623 RE: voltage-regulator current sources

And our reading from The Art of Electronics: The x Chapters includes:

  • §2x.2 pg 103-107 RE: Current-Source Problems and Fixes
  • §2x.3 pg 108-109 RE: The Cascode Configuration

Note that the 2nd edition of the x-Chapters is available for pre-order: The Art of Electronics: The x-Chapters 2.

When we continue next week we will do the various exercises we ran out of time to do today, and build some current sources, starting probably with a BJT version.

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

p.s. today I added BJT and Cascode to my spell check.


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!

Yum Cha 13-in-1 Multi-function Digital Display USB Voltage Current Power MeterThis is an image of the product.

Let’s go shopping!