Product Overview
Three-Terminal +12V Fixed Linear Regulator TO-220 - Fairchild MC7812C
Condition
Unused, New Old Stock (NOS). Visual inspection shows no signs of installation or damage. Part of our ongoing recovery from legacy electronics supply chains. No original retail packaging included unless shown.
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Product Overview
Fairchild MC7812C is a three-terminal positive fixed voltage regulator designed to provide a stable +12V DC output from a higher unregulated DC input. Part of the industry-standard 78xx regulator family, it is widely used in linear power supply designs for industrial controls, instrumentation, and embedded electronics. The MC prefix denotes compatibility with the original Motorola standard, and Fairchild production reflects a legacy era of through-hole power management components now largely replaced by newer manufacturing lines. This device simplifies power supply design by integrating internal current limiting, thermal shutdown, and safe-area protection into a single TO-220 package.
Key Features
- Fixed +12V DC output (±4% typical accuracy)
- Output current up to 1A to 1.5A with proper heat sinking
- Maximum input voltage 35V DC (absolute maximum)
- Typical dropout voltage approximately 2V
- Internal thermal overload protection
- Internal short-circuit current limiting
- Ripple rejection approximately 71 dB at 120 Hz
- Commercial temperature range 0°C to +125°C
- Three-terminal configuration: Input, Ground, Output
- Common TO-220 through-hole package
Applications
- Linear power supplies for 12V logic and control circuits
- Industrial control panels requiring regulated DC rails
- Bench-top electronics projects and prototyping
- Repair of vintage equipment designed around 7812 regulators
- Audio preamp and signal processing power sections
- Embedded systems needing simple, low-noise 12V regulation
- Educational labs demonstrating linear regulation principles
Frequently Asked Questions
Will this work as a replacement for other 7812 regulators?
Yes. The MC7812C follows the standard 78xx pinout and electrical characteristics, making it pin-for-pin compatible with most 7812 linear regulators in a TO-220 package. Always verify package style and thermal requirements in your design.
What input voltage is required for proper regulation?
For stable 12V output, the input should typically be at least 14V DC due to the approximate 2V dropout requirement. Higher input voltages increase heat dissipation.
Does this regulator require external components?
Yes. For stable operation, designers typically use a 0.33µF capacitor on the input and a 0.1µF capacitor on the output, placed close to the device, to prevent oscillation.
How much heat will it generate?
As a linear regulator, it dissipates power equal to (Vin − 12V) × load current. Heat sinking is recommended when operating at higher input voltages or near maximum current.
Is Fairchild still manufacturing this part?
Fairchild Semiconductor was acquired by onsemi. Fairchild-branded MC7812C devices are typically legacy production and valued for direct compatibility in existing systems.
The 7812 series earned its reputation by surviving decades inside control cabinets and lab gear. If your design needs a straightforward, proven 12V rail without switching noise, this classic regulator is ready for its next build.
