Here is a simple but less expensive inverter for the use of a small soldering iron (25W, 35W, etc) In the absence of essentials supply. It uses eight transistors and some resistors and capacitors. Transistors Q1 and Q2 (each BC547) form an astable multivibrator that produces 50Hz sign. The complementary outputs from the collectors of transistors Q1 and Q2 are fed to pnp Darlington driver ranges formed via transistor pairs Q3-Q5 and Q4-Q6 (utilising BC558 and BD140). The outputs from the rationale forces are fed to transistors Q7 and Q8 (each 2N3055) connected for push-pull operation. Use appropriate heat-sinks for transistors Q5 via Q8. A 230V AC main to 12V-0-12V, 4.5A secondary transformer (T1) is used.
The centre-tapped terminal of the secondary of the transformer is attached to the battery (12V, 7Ah), whereas the other two terminals of the secondary are related to the collectors of energy transistors T7 and T8, respectively. When you power the circuit the use of switch S1, transformer X1 produces 230V AC at its main terminal. This voltage can be utilized to warmth your soldering iron. Assemble the circuit on a generalpurpose PCB and house in an appropriate cupboard. Connect the battery and transformer with appropriate current-carrying wires. On the front panel of the box, fit power switch S1 and a 3-pin socket for connecting the soldering iron. Note that the rankings of the battery, transistors T7 and T8, and transformer may differ because these all rely on the burden (soldering iron).
Author : Sanjay Kumar
