# Tagged Questions

97 views

### Heating time of an aluminum plate

I'm designing a circuit for my 3D printer's aluminium heating plate (200x200 mm) and I wanted to be sure before buying resistors. Also, I'm using a Sanguinololu 1.3a. I want it to heat at 120° fast. ...
98 views

### Replacing a 5v to 3.3v converter

I am currently following this guide for modding an Airport Express for automotive use. It recommends using a AMS1117-3.3 regulator along with a USB power adapter to power the Airport Express. I was ...
92 views

### Connecting headphones to mcu

We need to connect a small speaker- a headphone one, to an Microchip Pic. I don't know whats the resistance of such speaker(it's very small) but I guess it's 8-ohm. (We are only using one headphone ...
79 views

### Step Voltage Down

I have an Arduino and several Strings of LEDs being powered by a wall wort. The LED portion is fine as is, however the Arduino has an ethernet shield attached and it is getting very hot when on. The ...
152 views

### Powering large LED array

I have a large LED array (huge, actually). It's 38 rows x 76 columns (2888) LEDs in total. The LEDs are 3mm, rated at 2.0 forward voltage and 20mA. The 38 rows (positive) are multiplexed using ...
185 views

### Does a power supply GND connection need a resistor?

I am creating a power supply for my work station, and I have a input of 13.5 - 19V DC from a converter on POWER_JACK. From this input voltage I want to derive 12V, ...
76 views

### How to find τ in these circuits?

I know that $τ = \frac{L}{R}$, but what is $R$ in this formula? It seems to be the total resistance, but how to find it in the schematics?
399 views

### How do I know where to place resistors on my circuit?

Some of the books I have state that power comes from the negative terminal on the power supply.If that is the case, the circuit starts from the negative right? Say I have a simple circuit with a 6v ...
502 views

### Switched bleeder resistor on a capacitive power supply

I posted a more vague version of this question a few days ago here and this question was linked as being similar. Answers in both threads were extremely helpful and were along the lines I was ...
138 views

### How many watts will the resistor in this naîve PSU dissipate?

One would be inclined to think the average current on resistor R would be exactly the same as in the load L, but I'm not so sure of that fact, due to the effect of the (big, 1000uF+) capacitors. ...
560 views

### Limiting the short circuit current of a power supply

I'm using a repurposed ATX power supply for my hobby projects since it's got 3.3/±5/±12 outputs, all of which are really convenient. But one thing I didn't really think about until I slipped my probes ...
160 views

### Cigarette lighter case mod [closed]

(Apologies in advance if this question is out of scope of this stackexchange but I wasn't really sure where else to post it. Any help, advice, useful links would be really appreciated though) I have ...
560 views

### Limiting current from a 5v power supply [duplicate]

Possible Duplicate: Choosing power supply, how to get the voltage and current ratings? I have a 5V / 1A regulated supply. I'm thinking of using it to power a PCB which asks for 5V and ...