This week we will also take our first test
- the ohm's law / power formula Series and Parallel exercise. All
homeowrks and exercises must be handed in. We will also begin soldering
exercises, starting with making a simple clip lead, then on to making an
XLR microphone cable.
week, you absolutely MUST be reading chapter's 5-8. Next week
we will learn Transformers and AC-to-DC conversion,
This is a problem-solving lab. The
lamps have a cold resistance that can be directly measured and a hot resistance
that must be indirectly measured. Once again, we get to sharpen out
CIRCUIT BOARD SOLDERING
RECTIFICATION: Converts Alternating Current (AC) to Direct Current
There are many ways to convert AC to DC as
you will see on this page. Each Rectifier type can be thought of
as application-specific, some are for high current loads (like motors and
power amps) and some for low current loads (like phantom power).
Keep in mind that the AC voltage is RMS, which is roughly 70% of the peak
to peak value. This is why the 'predicted' output voltage is stated
as 'approximate,' because the efficiency is Load Dependent.
Unloaded, the DC voltage out will be higher
than the AC voltage in, because the AC voltage is stated in RMS terms,
but without a load the peak of the sinewave charges teh capacitors, yielding
a higher voltage.
Zener diodes are used to regulate the voltage
- to 'clamp' it so that it does not go higher than intended.
FIGURE-1: Half-Wave Rectifier.
If the transofrmer supplies 10 voltsACrms, then the recitifed output will
be approximately 10volts DC
FIGURE-2: A simple voltage-doubler
rectifier can derive two voltages from a single transformer winding.
Like the circuit above, 10-volts AC will yield approximately 10-volts DC,
only now, with two diodes, there will be both plus and minus 10-volts DC
that's two voltages referencing 'common,' which the symbol implies is also
ground, or a single dose of 20-volt DC (from plus-to-minus, ignoring
FIGURE-3: Full-Wave Rectifier
FIGURE-4: Full-Wave Bridge Rectifier
FIGURE-5: Bi-polar Full-Wave Bridge