This decoder circuit also serves to change the 5-bit binary numbers to decimal to be displayed by seven segments. This decoder has a 5 pin input PA, PB, PC, PD PE and 14 pin output marked a, b, c, d, e, f and g.
For example, if the input PA, PB, PC, PD, PE = 11 01 0, then after the translated by the decoder will produce numbers a, b, c, d, e, f, g (MSD) = 10 0 1 1 1 1 and a, b, c, d, e, f, g (LSB) = 0 0 1 0 0 1 0. These numbers indicate that the negative pole (cathode) of the LED in a particular segment of a low voltage bias (0) so that the lights forming the number "12" on the seven-segment display devices. For more details can be seen in the picture
For example, if the input PA, PB, PC, PD, PE = 11 01 0, then after the translated by the decoder will produce numbers a, b, c, d, e, f, g (MSD) = 10 0 1 1 1 1 and a, b, c, d, e, f, g (LSB) = 0 0 1 0 0 1 0. These numbers indicate that the negative pole (cathode) of the LED in a particular segment of a low voltage bias (0) so that the lights forming the number "12" on the seven-segment display devices. For more details can be seen in the picture
In the circuit above using Seven Segment (7 Segment ) commond anode type. The principle works is, if the input pin Seven Segment a, b, c, d, e, f, g given voltage 0 volts, the LED on the Seven Segment props will be forward biased and turned to form a specific figure.
The seven segments can also be supplied with higher voltage (up to 18 V) but you have to replace the R 22 ohm with a greater value; morever, a suitable mast Rext be Chosen
Here is the truth table of the IC TDA4092 decoder
Absolute maximum rating IC TDA4092
- Supply voltage…………….... 10 V
- Input voltage……………….. .10 V
- Off state output voltage…...... 20 V
- Output current………………. 22 V
- Total power dissipation ….. ... 0.8 mW
- Storage and junction storage… -25 to 150 C
- Operating temperature………. 0 to 70 C