I do not know how to link pictures with a post, so I am just placing the
links below. Link 1 is for a 555 circuit, Link 2 is for house electrical
connection, and Link 3 is for fifty different 555 circuits.
In the picture in Link 1, the top 555 Sinewave output picture might help.
The output is similar to a sinewave, but it is above 0 volt. If using a 12 volt
suppply, the output would be about 11 volts and up to 200 mA. The output
would need to be raised somehow.
Link 2 shows how U.S. houses are connected to the grid. In the top left side
you will notice that the input to the transformer is split on the secondary,
and the wave forms are "out of phase" by 180 degrees.
If you take the output from the 555 chip, amplify it, use a RC low
pass filter to get a sinewave, then use a transformer that has a split
secondary, would that work?
Link 1:
http://www.talkingelectronics.com/projects/50%20-%20555%20Circuits/images/555-Osc-1.gifLink 2:
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/hsehld.html#c1Link 3:
http://www.talkingelectronics.com/projects/50%20-%20555%20Circuits/50%20-%20555%20Circuits.html#BTHE SIMPLEST 555 OSCILLATOR
The simplest 555 oscillator takes output pin 3 to capacitor C1 via resistor R1.
When the circuit is turned on, C1 is uncharged and output pin 3 is HIGH. C1
charges via R1 and when Pin 6 detects 2/3 rail voltage, output pin 3 goes LOW.
R1 now discharges capacitor C1 and when pin 2 detects 1/3 rail voltage, output
pin 3 goes HIGH to repeat the cycle. The amount of time when the output is HIGH
is called the MARK and the time when the output is LOW is called the SPACE.
In the diagram, the mark is the same length as the space and this is called 1:1
or 50%:50%. If a resistor and capacitor (or electrolytic) is placed on the output,
the result is very similar to a sinewave.
IMPROVING THE SINKING OF A 555
The output of a 555 goes low to deliver current to a load connected as shown in the
circuit below. But when the chip is sinking 200mA, pin 3 has about 1.9v on it. This
means the chip does not provide full rail voltage to the load. This can be improved by
connecting pin 7 to pin3. Pin 7 has a transistor that connects it to 0v rail at the same
time when pin 3 is LOW. They can both be connected together to improve sinking
capability. In this case the low will be 800mV for 200mA instead of 1900mV, an
improvement of 1100mV. This will add 1v1 to the load and also make the chip run
cooler.
Hope some of this might help,
Bob