Need Help Understanding Voltage Drop in My DIY Power Supply Circuit

[slangwhanger]

I’m pretty new to electronics and recently built a simple adjustable DC power supply using an LM317 regulator. It works fine most of the time, but I’ve noticed that when I connect even a small load (like a 12V motor or a few LEDs), the output voltage drops quite a bit — sometimes by almost a full volt.

I’m using a 15V DC input from a wall adapter, and the output is set to around 12V. I’ve got 100µF caps on the input and output as per the datasheet, but I’m wondering if maybe my power source or wiring is the problem?

Could this be because of the adapter’s current limit, or am I missing something obvious in my design? Any advice or troubleshooting tips would be really appreciated!

Thanks in advance
Geometry Dash

 

[bertus]

Hello,

How much current does the motor draw?
When the output current rises, the voltage drop on the regulator rises.

Does the input voltage drop when the output voltage drops?

Bertus

 

[Martaine2005]

Give the full specifications of your 15V adapter.
Even a small motor can draw many times its current requirements on startup.

 

[davenn]

I’m pretty new to electronics and recently built a simple adjustable DC power supply using an LM317 regulator. It works fine most of the time, but I’ve noticed that when I connect even a small load (like a 12V motor or a few LEDs), the output voltage drops quite a bit — sometimes by almost a full volt.

I’m using a 15V DC input from a wall adapter, and the output is set to around 12V. I’ve got 100µF caps on the input and output as per the datasheet, but I’m wondering if maybe my power source or wiring is the problem?

Could this be because of the adapter’s current limit, or am I missing something obvious in my design? Any advice or troubleshooting tips would be really appreciated!

Thanks in advance
Geometry Dash

and show us your circuit please