This  power inverter uses only 9 electronic components. This inverter circuit will turn 10 to 16VDC into 115V / 60Hz square wave AC power. It was able to operate AC equipment up to 25W.

The first section of the 555 timer is wires as an astable oscillator with R2 and C1 setting the frequency. The output is available at pin 5. The second section is wired as a phase inverter. That output is available at pin 9. Resistor R3 and R4 keep output transistor Q1 and Q2 from loading down the oscillator.

Read more about 25W Inverter circuit

This is a simple audio mixer circuit diagram:

You can add some resistors in parallel connection for more audio input. To adjust the volume for each input channel, add linear trimmer or potentiometer with configuration: pin1> ground; pin2>output; pin 3>input.

Wanna to build an inverter circuit..? This is an ordinary transistorised inverter circuit capable of driving medium loads of the order of 40 to 60 watts using battery of 12V, 15 Ah or higher capacity. This inverter will convert 12V DC input to become 230V AC in output.

Transistors T1 and T2 (BC548) form a 50Hz multivibrator. For obtaining correct frequency, the values of resistors R3 and R4 may have to be changed after testing. The complementary outputs from collectors of transistors T1 and T2 are given to PNP darlington driver stages formed by transistor pairs T3-T4 and T6-T7 (utilising transistors BD140 and 2N6107).

A trimmer or preset is a miniatur adjustable electrical component. It is meant to be ordered aright when installed in whatever device, and never seen or keyed by the device’s user. Trimmers can be potentiometers or varco (variable capacitors – trimmable inductors subsist but are rattling uncommon). They are ordinary in exactitude circuitry similar to  A/V components, and may need to be adjusted when the equipment is serviced. Unlike some another variable controls, trimmers are mounted direct on circuit boards, overturned with a small screwdriver and rated for some less adjustments over their lifetime.

Trimmers become in a difference of sizes and levels of precision; for example, multi-turn cut potentiometers exist, in which it takes individual turns of the fitting propellor to accomplish the modify value, allowing for rattling broad degrees of accuracy.

This in a really simple electronic buzzer circuit based on timer IC NE555. The IC 555 act as astable multivibrator which will generate audio signal frequency. The frequency value is depended the value of 56K resistor and 10nF (0.01 uf) capacitor… you may replace the 56K resistor with a variable resistor to adjust the frequency.