# Questions tagged [lm317]

3-terminal adjustable linear regulator

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### Is my heat sink calculation for the LM317 correct?

Using the formula PowerDissipated = (Vin - Vout) * Iout where: Vin = 12 V Vout = 2 V Iout = 450 mA Power dissipated = (12 - 2) x 0.45 = 4.5 W And heat sink value = (...
44 views

### LM317 low output current

I need to make a 1.5 V voltage source for a motor with maximum current drain 1 A. I made this circuit: The output voltage without load is 1.46 V, which is fine. When I connect a load resistor which ...
77 views

### Will this LM317 Circuit work for my application?

I am attempting to design a circuit to charge lithium 18650 batteries is a 3S configuration. I understand that a BMS is recommended, but I am not concerned with that. I have built this LM317 circuit (...
686 views

### Op Amp-based CV LM317 power supply

As many others before, I'm aiming to build my own simple CC CV lab bench PSU based on the LM317 regulator. Now, I've defined most of the circuitry, but I'm stuck with a particular design choice ...
107 views

### Dual channel linear power supply

As a learning project, I'm trying to create a simple linear power supply using LM317. The basic circuit is well documented on internet, but I want to create a variant that allows me to have multiple ...
40 views

### how to choose/design a capacitor value for surge current(for protection) for DC brush motor?

I am driving a DC BRUSH Motor at 30.V.D.C and the current is 300 Millie ampere, it is powered by L.M.317 I.C .My sir is suggesting to provide a capacitor as a protection form surge/peak current ...
139 views

### How does the LM317 bypass adjustment terminal reduce ripple amplification?

According to the LM317 datasheet it says that the adjustment terminal must be bypassed to ground to improve ripple rejection, so that the ripples aren't amplified. Could anyone explain how this is ...
70 views

### LM317 digitally-controlled constant current power supply

I'm designing and simulating (with the intention of building) a lab power supply. I like a challenge so I'm trying to make it digitally controlled (also because I'm a programmer). I'm doing this for ...
57 views

### Driving strings of high power LEDs - different ways with fault protection

I'm trying to find the best method for driving around 30 x white LEDs plus 10 x RGB. The power supply can be 24V. The LEDs will be dimmable, 3W or 1W, 0.350A or 0.7A (I'd need to limit the current a ...
69 views

### Variable Current Lead Acide Battery Charger

Digitally controlling charge voltage with some regulator like Lm317 is a matter of using some resistor and transistor as stated in lm317 datasheet to select from multiple pre defined voltage. But what ...
101 views

### What is the voltage drop across a TIP41c when it passes 2.9A for long durations?

simulate this circuit – Schematic created using CircuitLab I'm having trouble understanding from the datasheets what exactly happens when I put a circuit as follows: The two 20W LED don't have a ...
107 views

### LM317 / linear regulator, estimate of heat capacity

Quick question - what do you think the heat capacity of a LM317 might be? The use case is that I want to ignite e-matches, which requires are short duration high current and would prefer to just use ...
41 views

### Ni-MH battery charging issue - custom built transformers, LM317 gets warm

I had one variable voltage power supply built and I have been using it frequently. Although I had no issue until charging Ni-MH and Ni-Cad batteries with this power supply. Lead acid battery, ...
50 views

### Higher input current than output current in LM317

I am doing a power supply to a TFT Display that works with 3.3V, my main supply is 12V and TFT current draw is approximately 150mA (A simple schematic of my circuit is below). I put two LM317 because ...
167 views

### LM317 using 2N2222 as current limit

I am trying to build a current limiting circuit using LM317. The goal is to limit output current to ~150mA with 25V input and output at >20V. I built the circuit according to ST datasheet, using the ...
145 views

### What do you think about my PSU design?

I have designed a symetrical PSU using LM317, LM337 plus power BJTs. The desired output range is at least 24V-2V @ 6A max. Altough not shown in the schematic, i plan to add power resistors and a ...
316 views

### DC 30v Adjustable PSU using Lm317

This is the adapter i got in My hand I need a cheap diy stable circuit for making an Adjustable PSU using LM317 Voltage Regulator. I got a adapter with output power supply of DC 30v 400mA. I need a ...