110W AUDIO AMPLIFIER WITH TRANSISTOR BDW83D/BDW84D CIRCUIT SCHEMATIC DIAGRAM

110W AUDIO AMPLIFIER WITH TRANSISTOR BDW83D/BDW84D CIRCUIT SCHEMATIC DIAGRAM
power audio amplifier which using power transistor BDW83D and BDW84D. Copyright belong to Smart Kit.

FM TRANSMITTER WITH 2 TRANSISTORS SCHEMATIC DIAGRAM

FM TRANSMITTER WITH 2 TRANSISTORS SCHEMATIC DIAGRAM
The coil L1 was consist of 7 turns on a quarter inch plastic former with a tuning slug. The tuning slug is adjusted to tune the transmitter. Actual range on this prototype tuned from 70MHz to around 120MHz. The aerial is a few inches of wire. Lengths of wire greater than 2 feet may damp oscillations and not allow the circuit to work.

CIRCUIT TRANSISTORIZED INVERTER 60W 12V DC TO 230V AC SCHEMATIC DIAGRAM

CIRCUIT TRANSISTORIZED INVERTER 60W 12V DC TO 230V AC SCHEMATIC DIAGRAM

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). The outputs from the drivers are fed to transistors T5 and T8 (2N3055) connected for push-pull operation.

Somewhat higher wattage can be achieved by increasing the drive to 2N3055 transistors (by lowering the value of resistors R7 and R8 while increasing their wattage). Suitable heatsinks may be used for the output stage transistors. Transformer X1 is a 230V primary to 9V-0-9V, 10A secondary used in reverse.