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TDA2003 is a cheap amplifier that is designed to run on single rail power supplies (unipolar). It provides a high output current capability (up to 3.5A), very low harmonic and cross-over distortion.  18W TDA2003 bridge Circuit Diagram TDA2003 bridge 18W amplifier TDA2003 can be used as an BCL (bridge amplifier) and car deliver up to 18W.

Using a few diodes and a LED, you can make a nice indicator as shown in associated schematic diagram that can be used for a lot of applications (with a bit of luck). It’s quite suitable for use in series with a doorbell or thermostat (but don’t try to use it with an electronically con-trolled central-heating boiler!). This approach allows you to make an attractive indicator for just a few pennies. The AC or DC current through the circuit causes a voltage drop across the diodes that is just enough to light the LED. As the voltage is a bit on the low side, old-fashioned red LEDs are the most suitable for this purpose. Yellow and green LEDs require a somewhat higher forward voltage, so you’ll have to first check whether it works with them. Blue and white LEDs are not suitable. You also don’t have to use modern high-efficiency types (sometimes called ‘2-mA LEDs’ or ‘3-mA LEDs’). If a DC current flows through the circuit and the LED doesn’t light up, reverse the plus and minus leads. Bridg...

Removing and replacing the saddles on a Tune-O-Matic (TOM) bridge can be a confusing and somewhat fiddly process, but really isn’t that difficult. Note, though, that there have been several variations of the TOM bridge, and the process differs slightly from model to model. Also important to note is that each different bridge requires a different set of Graph Tech saddles, so make sure you buy the right ones. Go here to check which model you need: http://www.graphtech.com/products.html?SubCategoryID=34 Here’s the patient. It’s a 1993 Gibson Les Paul Studio. If you look closely, you can see that the strings have started to make their own slots where they shouldn’t, though that's not the only reason for this upgrade. The bridge in question is a Nashville pre-2000 bridge, which means the required Graph Tech saddles are part number PS-8500-00. Once the strings are removed, the bridge lifts off very easily. In fact, be careful it doesn’t fall off when you aren’t paying attention (same go...