T&L Publications

Just because the battrery is not that old, does not mean that it is still good. Just a few good deep discharge events can reduce the capacity of a car battery while still having enough charge to start when recently charged.<p>Use an ammeter to measure the current into the yellow wire while the car i...

Forgive me for coming in at the end and not reading all the posts that led up to here.<p>Since you suspect that plugging in a board backward may have caused a failure, I want to give you a few general tips about that subject.<p>When you insert a device or a board backward you will most likly have ap...

Your idea has several parts to it.<p>1. Electromechanical actuator to move the locking knob to the correct positions or replace such a mechanism.<p>2. Apparatus to sense the "last use direction" of the door.<p>3. Logic and driver circuitry to recieve the sensor input and drive the actuator...

How many channels does your sound card support. If you have a 4 or 5 channel sound card, you can record the music onto the front L and R channels and use one of the rear or surround channel to record the trigger tones. This way, no one hears the control tones in the music.<p>There are plenty of soun...

In general, Yes. Depending on the chip and where it is in the circuit, the cap either helps to prevent noise in a chip from getting on a supply line or from being disturbed by noise already on that line.<p>For either of these purposes, it is best to place the cap as close to the supply pins as const...

If you are just looking to make a voltage divider then (rounding to 2V) just about any pair of resistors with a 2 to 1 ratio will work**. A 1 ohm and a 2 ohm or a 10k and a 20k will both get you 2V at the junction (node) between the two .<p>***But... The value of the resistors will limit the current...

Inspired by these posts about putting solar cells on a windmill, my creative sap started running a bit. (especially when pointed out that a windmill can be a noisy eyesore.)<p>Imagine a tree-like structure with leaves made up of photo-electric cells and with stems and branches made up of piezo-elect...

I'm sure you can convert the output from any type of sensor to provide the necessary 5V digital input to the basic stamp indicating presense of water.<p>The unknown (to me) is where is the water and how much do you want to detect. Let me make a few assumptions for this example.<p>Take for example on...

"Alright then, two (2) AA cells. "<p>2 Alkaline cells would add up to 3.0V fully charged (and forget it if someone tries to use rechargables instead - which they will - only 2.8V) which is less than 3.3V operating voltage right off. just as well, even a little discharge of the batteries wo...

Use a regulator. Any dropping diode/resistor combination would assume the source voltage and current is constant. Batteries are not constant voltage, the voltage diminishes as it dies. The rate at which the voltage decays through use can usually be gotten from the battery spec sheet online.<p>A zene...

Assuming your disk is clean and free of obvious scratches.<p>The buffer certainly has a lot to do with how well a drive can compensate for gaps in the serial data stream coming from the pickup head off the disk. This used to be a big selling feature on CD players years ago but I think all newer driv...

A dirty 12V supply will probably work fine.<p>12V amplifiers designed to drive 4 ohm speakers have a maximum wattage of 36W (V^2/R). Since yours is more than 36W then the amplifier must boost the voltage to more than 12V before applying it to the sources of the final amplifier. It stands to reason t...

fishing around an unknown PCB for an input to an amplifier without a schematic can be tricky but not impossible if you have some experience.<p>You can probably get away with simply paralleling the internal speaker with your external speaker. If there is too much noise on the external speakers or it ...

It is my understanding that Digital phones use the lowest power setting to achieve acceptable transmission quality. This saves power for the battery but sometimes causes the phone to have borderline connections. It is as though the signal strength bars can also represent the inverse of the output po...

In production, they are probably silk-screened.<p>Silver pen might work (not knowing what plastic or how much bend. You might try coating the wire with nail polish (if not flexing too much) or silicone caulk (insulative and very compliant) to protect it from the oxidation, scratches and flaking.<p>M...