Uploaded June 2026 | Updated September 2026, 2 weeks ago
Learn how voltage regulators actually work and how to design and build one.
Check out PCBWAY➡️ pcbway.com for PCB's, 3D printing and CNC at expectational value and design PCB's with Altium ➡️ altium.com/yt/engineeringmindset
Learn how an LM317 adjustable voltage regulator turns unregulated DC into a smooth, stable output for electronics projects. In this video, we build a DIY adjustable power supply, explain how resistors and a potentiometer set the output voltage, explore dropout voltage, heat dissipation, protection diodes, filter capacitors, and even look inside the regulator using a laser teardown to understand how it really works. Perfect for beginners learning electronics, PCB design, and power supply circuits.
🛠️ Build the kit yourself 🛠️
Want to build the kit at home, click here:👉 tinyurl.com/Voltage-Regulator-Kit
Want to order just the PCB, click here:👉 tinyurl.com/Order-PCB
Coupon Code: PCBWay-TEM10
🎁 Design, review, and manage PCBs in one connected environment with Altium Designer.
Get a 30-day free trial here ➡️ altium.com/yt/engineeringmindset
**PCBWAY Promotional Code T&C**
Coupon Code: PCBWay-TEM10
Offer: $10 off orders over $30
Applicable Services: PCB (Assembly), CNC, 3D Printing, and other PCBWay services (excluding shipping)
Validity: The code is available for 3 months and expires 6 months after each individual redemption
Redemption Limit: One-time use per person
Quantity: 200 codes available
✨ With special thanks to these amazing people ✨
A. Cabello, R Charlery, T Champion, R. Elskamp, Wiggie, P Bramble, R. Liu, M Bellis, C. Eastman, W. Schnur, davekroil, U Pehlivanoğlu.
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00:00 Introduction: How Adjustable Voltage Regulators Work
00:23 Why We Need Voltage Regulators in Electronics
01:11 Fixed vs Adjustable Voltage Regulators Explained
01:44 LM317 Voltage Regulator Pinout & Circuit Overview
02:32 The Hidden 1.25V Reference Inside the LM317
02:47 How Resistors Set the Output Voltage
03:04 Voltage Regulators in Real Electronic Devices
04:26 Voltage Divider Theory for LM317 Circuits
05:06 The LM317 Constant Current Trick Explained
06:02 How the LM317 Calculates Output Voltage
06:55 How a Potentiometer Controls Voltage
07:30 Common Potentiometer Failure Modes & Protection
09:03 Why Linking Potentiometer Pins Improves Reliability
09:41 Preventing Unstable Low-Voltage Operation
10:24 LM317 Output Voltage Formula Explained
10:48 Choosing the Correct Potentiometer Value
12:00 LM317 Dropout Voltage & Input Voltage Requirements
12:46 Reverse Polarity Protection with Diodes
13:45 Why Linear Regulators Get Hot
14:26 Heat Sinks, Insulation & Thermal Management
15:11 Input Filtering Capacitors Explained
16:04 Output Capacitors & Load Transient Response
16:37 Reducing Noise with the Adjust Pin Capacitor
17:05 Protection Diodes for LM317 Stability
17:52 Power Indicator LED Design Considerations
18:50 Inside the LM317: Laser Teardown & Internal Circuit
19:24 LM317 Internal Components Explained
20:43 How the Voltage Reference Works
21:27 Op-Amp Feedback Control Explained
23:28 LM317 Regulation Example Step-by-Step
25:24 Building the Adjustable Power Supply Yourself
26:37 Breadboard Testing & PCB Assembly Guide
Learn how voltage regulators actually work and how to design and build one.
Check out PCBWAY➡️ pcbway.com for PCB's, 3D printing and CNC at expectational value and design PCB's with Altium ➡️ altium.com/yt/engineeringmindset
Learn how an LM317 adjustable voltage regulator turns unregulated DC into a smooth, stable output for electronics projects. In this video, we build a DIY adjustable power supply, explain how resistors and a potentiometer set the output voltage, explore dropout voltage, heat dissipation, protection diodes, filter capacitors, and even look inside the regulator using a laser teardown to understand how it really works. Perfect for beginners learning electronics, PCB design, and power supply circuits.
🛠️ Build the kit yourself 🛠️
Want to build the kit at home, click here:👉 tinyurl.com/Voltage-Regulator-Kit
Want to order just the PCB, click here:👉 tinyurl.com/Order-PCB
Coupon Code: PCBWay-TEM10
🎁 Design, review, and manage PCBs in one connected environment with Altium Designer.
Get a 30-day free trial here ➡️ altium.com/yt/engineeringmindset
**PCBWAY Promotional Code T&C**
Coupon Code: PCBWay-TEM10
Offer: $10 off orders over $30
Applicable Services: PCB (Assembly), CNC, 3D Printing, and other PCBWay services (excluding shipping)
Validity: The code is available for 3 months and expires 6 months after each individual redemption
Redemption Limit: One-time use per person
Quantity: 200 codes available
✨ With special thanks to these amazing people ✨
A. Cabello, R Charlery, T Champion, R. Elskamp, Wiggie, P Bramble, R. Liu, M Bellis, C. Eastman, W. Schnur, davekroil, U Pehlivanoğlu.
⚡🛠️ TOOLS YOU NEED 🛠️⚡
*******************************
Get this electronics book ➡️ amzn.to/41cCJPk
Professional Multimeter -➡️ amzn.to/3xu2Vaw
Good multimeter -➡️ amzn.to/3xrbuTd
Professional clamp meter ➡️ amzn.to/4140FnK
Good Clamp meter ➡️ amzn.to/3xqt2is
Outlet tester ➡️- amzn.to/3kavg2l
Energy monitoring plug ➡️ amzn.to/3SkfPl7
Battery tester -➡️ amzn.to/3S3fHWI
Basic electronics ➡️ kit amzn.to/3xuLiqS
MY FAVOURITE GEAR
🎥 My camera - amzn.to/3YCZ7Q9
🎤 My Microphone - amzn.to/3YYXsUC
⌨️ My Keyboard - amzn.to/3lBsl33
🖥️ My monitor - amzn.to/415BGjW
🎧 My headphones - amzn.to/3lN7R7u
👋 SOCIALISE WITH US 👋
*******************************
👉FACEBOOK: facebook.com/theengineeringmindset
👉TWITTER: twitter.com/TheEngMindset
👉INSTAGRAM: instagram.com/engineeringmindset
👉WEBSITE: Http://TheEngineeringMindset.com
00:00 Introduction: How Adjustable Voltage Regulators Work
00:23 Why We Need Voltage Regulators in Electronics
01:11 Fixed vs Adjustable Voltage Regulators Explained
01:44 LM317 Voltage Regulator Pinout & Circuit Overview
02:32 The Hidden 1.25V Reference Inside the LM317
02:47 How Resistors Set the Output Voltage
03:04 Voltage Regulators in Real Electronic Devices
04:26 Voltage Divider Theory for LM317 Circuits
05:06 The LM317 Constant Current Trick Explained
06:02 How the LM317 Calculates Output Voltage
06:55 How a Potentiometer Controls Voltage
07:30 Common Potentiometer Failure Modes & Protection
09:03 Why Linking Potentiometer Pins Improves Reliability
09:41 Preventing Unstable Low-Voltage Operation
10:24 LM317 Output Voltage Formula Explained
10:48 Choosing the Correct Potentiometer Value
12:00 LM317 Dropout Voltage & Input Voltage Requirements
12:46 Reverse Polarity Protection with Diodes
13:45 Why Linear Regulators Get Hot
14:26 Heat Sinks, Insulation & Thermal Management
15:11 Input Filtering Capacitors Explained
16:04 Output Capacitors & Load Transient Response
16:37 Reducing Noise with the Adjust Pin Capacitor
17:05 Protection Diodes for LM317 Stability
17:52 Power Indicator LED Design Considerations
18:50 Inside the LM317: Laser Teardown & Internal Circuit
19:24 LM317 Internal Components Explained
20:43 How the Voltage Reference Works
21:27 Op-Amp Feedback Control Explained
23:28 LM317 Regulation Example Step-by-Step
25:24 Building the Adjustable Power Supply Yourself
26:37 Breadboard Testing & PCB Assembly Guide
