12/220V Converter With Sine Output

12/220V Converter With Sine Output
How it work : The master oscillator, a voltage reference and comparator collected on DA2. External elements DD1 and DD2 repeated internal structure of the TL494, in the part that works is unstable at low frequencies (false positive D-flip-flop). Further, using the low-pass filter suppresses the upper harmonics of the PWM. LPF consists of two parts. First-DA1.1, with a smooth lowpass characteristic curves. Second-DA1.2 notch filter with a frequency of 150 Hz suppression. The analysis shows that the PWM

12 VDC TO 117 VAC / 60HZ POWER INVERTER

12 VDC TO 117 VAC / 60HZ POWER INVERTER
Capacitor C5 and potentiometer R12 figure out the frequency of the output signal at pin number 3 of IC1, the 555oscillator. The output signal is differentiated by C3 and C4 before it's input to the base of power transistors Q1 and Q2 through diodes D1 and D2, respectively. The signal from IC1 is adjusted to 120 Hertz, because the flip-flop created by transistors Q3 and Q4 splits the frequency by two. (more…)