Car Light Dimmer for 12V Lamps
This circuit provides smooth brightness control for 12V car lamps using an operational amplifier (UA741) and a power transistor (2N3055). It allows continuous adjustment of light intensity without noticeable flicker, ideal for dashboard illumination or interior lighting applications.
The UA741 op-amp functions as a voltage comparator and control amplifier, generating a variable output based on the position of a potentiometer. This output drives the 2N3055 power transistor, which regulates the current supplied to the lamp.
As the control voltage varies, the 2N3055 adjusts its conduction, thereby changing the lamp’s brightness smoothly from dim to full intensity.
The circuit operates directly from a 12V DC automotive supply and features:- Stable linear dimming control
- Low heat generation compared to resistive dimmers
- High current handling via the 2N3055 transistor
This simple yet effective design demonstrates the practical use of an op-amp with a power transistor for analog control in automotive and lighting applications.
Adjust VR1 and VR2 to get time until door is open and presence light turn off.
Use heatsink in 2N3055 transistor.