Tinh hinh la sap den mua he rui. Minh co y tuong la lam mot cai kick dien don gian tu 12 VDC len 220VAC. Day la mach, cac ban xem thu...kaka.. luom dc tren mang
Error fix: Pin 7 and 2 were reversed. Original pinout was correct.
R1 = 10K
R2 = 100K
R3 = 100 ohm
R4 = 50K potmeter, Linear
C1,C2 = 0.1uF
C3 = 0.01uF
C4 = 2700uF
Q1 = TIP41A, NPN, or equivalent
Q2 = TIP42A, PNP, or equivalent
L1 = 1uH
T1 = Filament transformer, your choice
This DC-to-AC inverter schematic produces an AC output at line frequency and voltage. The 555 is
configured as a low-frequency oscillator, tunable over the frequency range of 50 to 60 Hz by Frequency
The 555 feeds its output (amplified by Q1 and Q2) to the input of transformer T1, a reverse-connected
filament transformer with the necessary step-up turns ratio. Capacitor C4 and coil L1 filter the input to
T1, assuring that it is effectively a sine wave. Adjust the value of T1 to your voltage.
The output (in watts) is up to you by selecting different components.
Input voltage is anywhere from +5V to +15Volt DC, adjust the 2700uF cap's working voltage
Replacement types for Q1 are: TIP41B, TIP41C, NTE196, ECG196, etc. Replacement types for Q2 are:
TIP42B, TIP42C, NTE197, ECG197, etc. Don't be afraid to use another type of similar specs, it's only a
If the whole thing is working, good. If not, relax and don't get frustrated. Do the following checks:
DC to AC Inverter With the 555 Page 1 of 2
1) You have connected the filament transformer in REVERSE yes?
2) If not, disconnect the power and reverse. If you have, disconnect the transformer and measure
the voltage after L1 and ground.
3) Just in case, GROUND for this circuit is same as negative (-).
4) Q1/Q2 are oposites, e.i. npn/pnp.
5) Is your 555 perhaps defective? Disconnect R3 from pin 3 and check pin 3 for a pulse.
6) Check your transistors to make sure they are not defective.
Back to Circuits page
Page Copyright © 2002 - Tony van Roon
DC to AC Inverter With the 555 Page 2 of 2