4-Bit Decimal Display

Display driver ICs are available in several standard implementations. This circuit makes use of a GAL 22V10 to drive two 7-segment displays without multiplexing. A 4-bit binary code at inputs A/B/C/D is converted to a decimal number. An example of an application is the ‘Audio Limiter (for DVD)’, but take note of the voltage levels! The multiplexers used there are driven by a 4-bit binary counter. This circuit will give a better indication of the behaviour and settings of the limiter.

Resistors:
R1-R9 = 820Ohm 
Capacitors:
C1 = 100nF ceramic
C2 = 2µ F2 63V radial
C3 = 220µ F 25V radial
Semiconductors:
D1 = 1N4002
IC1 = GAL22V10
IC2 = 78L05
LD1,LD2 = HDN1075