For medium-sized capacities up to 40 W PMPO, a traditional economical solution found in many car radios and traditional car audio players is the TDA2002 integrated circuit. Precisely because it is a component widely used by the aftermarket, besides being easy to find it has a very affordable price.
This amplifier can be powered with voltages from 8 to 18 V and its performance is an interesting solution for those cases where volume is capable of attracting the attention of many people such as alarms, warning systems, etc.
Two additional highlights in using this amplifier: easy to work with because it uses a TO-220 enclosure (like a power transistor) and requires few external components for amplifier implementation. In figure 1 we have the circuit of the basic version with voltage gain equal to 100.
The voltage gain is determined by the relationship between the values of R1 and R2. The resting current is 45 to 80 mA and the peak current reaches 1.8 A. The source must be capable of supplying this current.
In figure 2 we have the printed circuit board for the assembly of this amplifier.
Note that the integrated circuit must have a good heat radiator. Other features of this amplifier are the frequency response of 40 to 15 000 Hz and the sensitivity of 50 mV for power of 8 W with load of 2 ohms.
In figure 3 we have a power supply for this amplifier.
For a stereo version the current capacity of the transformer and the diodes must be doubled. The electrolytic capacitor must also be increased to obtain good filtration in this case.
MATERIAL LIST
Semiconductors:
CI-1 - TDA2002 (uPC2002) - integrated circuit
Resistors: (1/8 W, 5%)
R1 - 220 ohm
R2 - 2.2 ohm
R3 - 1 ohm
P1 - 47 k ohm - log - potentiometer
Capacitors:
C1 - 10 uF x 16 V - electrolytic
C2 - 470 uF x 16 V - electrolytic
C3, C6-100 nF - polyester or ceramic
C4 - 100 uF x 16 V - electrolytic
C5 - 1000 uF x 25 V - electrolytic
Several:
FTE - Speaker 2 or 4 ohm x 10 cm or larger
Printed circuit board, wires, heat radiator for the integrated circuit, solder, material for power supply, etc.
