7805 Steady
+5V Linear Regulator Tool
3.5 W
POWER DISSIPATION
41.7%
Efficiency
Efficiency
Required
Heatsink?
Heatsink?
Dropout Alert: If $V_{in} < 7V$, regulation will fail.
Always use 0.33µF input and 0.1µF output capacitors.
Always use 0.33µF input and 0.1µF output capacitors.
The 7805 is a Linear Regulator. It works by “burning off” excess voltage as heat. This makes it simple and noise-free, but it can be inefficient if the input-output gap is large.
The Core Formulas:
- The Thermal Trap: Many beginners think a TO-220 7805 can handle 1.5A easily. However, if you drop 12V to 5V at 1A, the regulator must dissipate 7 Watts. Without a massive heatsink, it will shut down in seconds.
- Capacitors are Mandatory: Linear regulators can oscillate (vibrate electrically) without decoupling capacitors. Place a Ceramic 0.33µF on the input and a 0.1µF on the output as close to the pins as possible.
- Efficiency: If your efficiency is below 50%, consider switching to a Buck Converter (DC-DC Switcher). They are drop-in replacements for 7805s and stay cool to the touch.