modified square wave inverter using the same 4017 that your circuit is using.
The main difference I notice with this one is there are NO diodes at the Output
Pins of the 4017, where yours has diodes. Both circuits so far are both using
Mosfets in the Output section. So I don't think the mosfets are the
diodes are removed from my circuit, the waveform will go haywire and
not produce the intended ones. I already designed and published a
simpler modified sine wave inverter circuit which is quite similar to
the above diagram you sent me,
Since my circuit is not a tried one, you better go for other proven options...........keep trying buddy, success is near.
Good Luck and Best Regards.
nice, as close to a PWM Chip can accomplish, Ok lets go through this
step by step.The other two schems. I sent you all use One 4017. Now in
order for our wave form to be produced, do we need both chips?What could
possibly cause the Mosfets to blow up.
One thing I did notice is that the Calculation for frequency is
not exact, an input frequency of 1200Hz does not give me 60 Hz at the
diode junction, it gives me like 64.367Hz. In order to achieve 60Hz the
input must be 1.086KHz. Is that normal??
circuits which are using single 4017 IC will produce crude
modification, whereas my circuits resolution (using 2 ICs) is more close
to a sine wave.
The mosfets or any device will blow-off in case its collector current exceeds it breakdown limit.
the transformer winding forms the collector load for the mosfets. The
transformer produces a high impedance to the devices only if they are
subjected to ACs, i.e. as long as the base of the devices receive an
oscillating voltage, otherwise the winding will just act like a short
and instantly blow-off the devices.
The two ICs in my PWM circuit
should conduct in tandem i.e. when IC1 is producing the clocks, IC2
should remain switched OFF and vice-versa, this becomes very important.
So, to get it checked we need to do following set-up:
diode junctions from the transistor basess, connect an LED each to both
the diode junctions and ground with a series resistor of about 1K.
reduce the clock frequency to about 1Hz by suitably adjusting the 4069
capacitor. The LEDs should generate the following pattern:
LED connected to IC1 should first go blink---blink----blink------blink
(IC2 LED being shut-off). Next its the turn of the LED connected to IC2,
it will behave just as above, this time the previous LED will remain
shut-off, this cycle should repeat itself.
The above test will prove the correctness of the circuit.
Let's do the above as the first step and once it is proved we can move ahead.