60W inverter using transistors

Here is the circuit diagram of a fully transistorized inverter that can drive up to 60W loads. Transistors Q1 and Q2 forms a 50Hz astable multivibrator. The output from the collector of Q2 is connected to the input of the Darlington pair formed by Q3 and Q4.Similarly the output of Q1 is coupled to the input of the pair Q5 and Q6. The output from the Darlington pairs drive the final output transistors Q7 and Q8 which are wired in the push pull configuration to drive the output transformer.

Circuit diagram.

Notes.

The circuit can be assembled on a vero board.

T1 can be a 230V primary to 9-0-9V, 6A secondary transformer.

Transistors Q4, Q6, Q7 and Q8 must be fitted with heat sinks.

Use a 12V, 7Ah battery for powering the inverter.

Slight adjustments can be made on the value of R3 and R4 to get exact 50Hz output.

Read More

240V to 110V AC Inverter

Using this circuit diagram, can be designed a very simple AC voltage converter, which converts the 240V AC power to a voltage of 110V.

Circuit can be successfully used to power electrical devices that require a supply voltage of 110V. If such a device is a purely resistive load, as electric radiator, letcon the circuit described below will be useful. Basically, this is a regulator that ensures the effective output voltage of 110 V. It can be fixed, of course, at another value for the output voltage, if desired.

The most reliable and accurate method for measuring the load voltage is using a voltmeter with real effective value (which indicates the effective value for voltage harmonic). If the voltage across the load is not correct, we change the value of R2.

Converter can be connected / disconnected from the remote by connecting a switch to 240 volts across REMOTE (jumper will be removed). In this case, command can be done with a voltage of 3-32 V, as shown in diagram. The optocoupler circuit presents the great advantage of isolation of control circuit from the network .

If using a TIC226triac type, the converter can supply currents up to 2 A. If the triac is mounted on a heatsink, the current can reach up to 4 A.

Read More

12 VDC to 120 VAC Inverter Circuit

12 VDC to 120 VAC Inverter Circuit

Ever bare a low ability 120volt AC ability antecedent for your car, van or truck? Well this ambit should do the ambush for you. It will accumulation 15 watts of AC ability to a device. It should ability lamps, shavers, baby stereos and baby appliances. If you draw to abundant ability the ambit will shut bottomward all by itself. The achievement of this ambit is a aboveboard beachcomber so there may be some apparent hum on audio units acquainted into it. To abate some of the hum access the amount of the achievement capacitor which is at .47uf now. That transistor in the ambit are aerial ability PNP transistors. Radio Shack allotment cardinal 276-2025 are acceptable ones to use or TIP32. The agent is a 24 volt 2 amp centermost broke accessory Radio Shack allotment cardinal 273-1512 or equivalent.

Read More

Inverter Window Comparator Wiring diagram Schematic

This is a simple Inverter Window Comparator Circuit Diagram ICl-c functions as a non inverting comparator, and ICl-a operates as an inverting comparator. Potentiometer Rl and fixed resistors R2 and R3 form a divider chain that delivers slightly different voltages to the two comparators. These voltages define the upper and lower limits of the schema`s switching window, which can be changed easily by varying R2 and R3. The LED glows only when the input voltage falls within the window region. 

Inverter Window Comparator Circuit Diagram

Read More

Panasonic Microwave Oven Inverter HV Power Supply

Nearly all Panasonic microwave ovens now use an Inverter, and are always labelled with “Inverter” on
the front.

The High Voltage Power Supply Unit (HV PSU)

The HV PSU measures 165mm x 105mm x 60mm and weighs 650g.

 At left is the control daughter board. In front of that on the main board are the opto-isolators for the control and status signals brought out to the green connector. Back left is the rectified mains filter choke. The mains rectifier and switching transistors can just be seen on the heatsink behind the transformer. The mains filter capacitor is at right rear. The HV rectifiers and filters (doubler) are right front – white wires are the HV output from the transformer. The green wire is for grounding the HV +ve. The two lugs t right are for connecting HV -ve and heater to the magnetron. The winding thatcan be seen on the transformer is the primary and is made from 3mm finely stranded wire.

Here’s a view of the control end: 

This is the high voltage end:

The schema for the HV PSU is below 

Notes about the schema:
1. Apart from the block diagram, there is no information on the Inverter cont(o)rol schema. The schema itself is centred on one large, unmarked IC, so no help there.

2. The control and status signals seem to be a digital stream (2-3v suggestsa 5V data stream). They are opto-isolated because the majority of the schema is at mains potential  (**BEWARE**). The part that isn’t is at 4kV (*** REALLY BEWARE ***)

3. The mains input side is monitored for both current and (under) voltage. No indication of what the control schema does with this information.

4. The mains filter capacitor (C702) is very small – only 4uF. In a “normal” switching supply, there is usually 220 or 470 uF in this position.

5. Q701 that does all the hard work is a very heavy duty IGBT – a GT60N90 - 900V @ 60 A. Q702 forms some sort of flywheel schema. This schema from a Toshiba IGBT application note looks similar:

6. The HV side has a full-wave doubler rectifier and is marked 4kV @  300mA. Unlike the classic microwave oven transformers (where one side of the winding is grounded), this means that the secondary must be well insulated from ground on both sides. A simple reconfiguration of the rectifier (replace the caps with diodes) into a bridge schema should yield 2kV @ 600mA (depending on the diode ratings)


7. The HV filter capacitors are only 8200 pF each, effectively giving 4100pF in the doubler. Considering that the inverter runs at about 30kHz, the reactance is equivalent to that  of a 5uF capacitor at 50Hz.


8. The positive side of the HV is grounded, so it’s a –4kV supply. Don’t simply swap the ground from the positive to the negative to get a +4kV supply, as the core of the transformer is also connected to this ground trace and will suddenly rise to 4kV above ground with disastrous and potentially fatal results. Instead, reverse the polarity of the rectifier diodes to get +4kV.

Source : By David Smith VK3HZ (vk3hz (*at*) wia.org.au)

Read More