Product Overview
One Regulator That Covers Every Rail You Did Not Stock
Condition
Listed New. The photographed device is representative of the current stock rather than the individual piece that ships. Under the camera the front face carries the Motorola M logo, the marking LM 317DS, and the lot code QGY037; lot codes vary from piece to piece across stock. All three leads are straight, full length, and uncut, with no bends and no solder visible in either frame. The reverse shows the bare metal mounting tab of a standard non-isolated TO-220, and the mounting hole is clean and unobstructed.
Same or next business day shipping from our Idaho warehouse. Honest pricing, no nonsense.
Online since 1999. We are here for our customers, with a no-hassle satisfaction guarantee.
Product Overview
The LM317 is the adjustable answer to the fixed 78xx series: a three-terminal positive regulator whose output is set by an external two-resistor divider instead of by the part number you happened to buy. It holds a nominal 1.25V reference between the output and adjust pins, which puts the usable output range at roughly 1.2V to 37V, and in this TO-220 package it will supply more than 1.5A with adequate heatsinking. Maximum input to output differential is 40V. The device carries internal current limiting, thermal overload protection, and safe area compensation, so a wrong load or an undersized heatsink backs it off instead of taking it out. The part in these photos is marked with the Motorola M logo and LM 317DS on the front face, matching the catalog part number. The full electrical grade implied by the DS suffix is not confirmed here - verify against the datasheet before use.
Key Features
- Adjustable three-terminal positive voltage regulator, output range roughly 1.2V to 37V
- Supplies more than 1.5A in the TO-220 package with adequate heatsinking
- Output voltage set by two external resistors around a nominal 1.25V internal reference
- 40V maximum input to output differential
- Internal current limiting, thermal overload protection, and safe area compensation
- Standard non-isolated TO-220 with bare metal tab and mounting hole, confirmed from the reverse photo
- Photographed sample marked with the Motorola M logo and LM 317DS on the front face
- Detail specific to the DS suffix is not confirmed - verify against the datasheet before use
Applications
- Building a variable bench supply where one transformer and one knob have to cover 3V through 30V
- Repairing vintage audio, lab, or test gear whose original LM317 has drifted or failed short of its rail
- Prototyping an odd rail - 3.3V, 9V, 15V - with a resistor pair instead of stocking five different fixed regulators
- Wiring the LM317 as a constant current source with a single resistor, for LED strings or simple battery charging
Frequently Asked Questions
How do I set the output voltage?
With two resistors. The LM317 maintains a nominal 1.25V between its output and adjust pins, and the divider you hang across that reference decides where the rail lands. Nothing about the part itself changes between a 5V design and a 24V design, which is why one drawer of LM317s replaces a shelf of fixed regulators.
Does it need a heatsink?
Usually, yes. This is a linear regulator, so everything between input and output gets burned off as heat in the tab. A 12V input dropping to 5V at half an amp is real wattage. The TO-220 tab and mounting hole are there for that reason, and the internal thermal shutdown is a safety net, not a cooling plan.
What does the DS suffix mean?
Not confirmed. The package in front of the camera is plainly a standard TO-220 and the marking plainly reads LM 317DS with the Motorola logo, which is what the listing states. If your design depends on a specific tolerance grade or temperature range, verify against the Motorola datasheet before use.
What was QGY037 on the front of the part?
A lot and date code, not a part number. It identifies the production run of the piece that sat under the camera. Other pieces in this stock will carry their own codes, so the electrical part number is what to match on, not the third line.
Why buy a few of these here instead of a bag of a hundred somewhere else?
Because most benches need two, not two hundred. You buy the exact count the job calls for - one to bring a dead supply back, three for a small run of boards, a couple more for the parts drawer - without paying for ninety-seven regulators that will sit in a static bag until you move house. Shipping is $8 flat rate and free once your order passes $28, and orders leave our Idaho warehouse the same or next business day.
That M on the front is from the years when Motorola still built its own analog silicon, and the LM317 was the part every bench reached for when a rail had to land somewhere the catalog did not cover. Pick your two resistors, and it goes right back to work.
