Darlington Driver (ULN2803A)

This is an 18 pin ‘chip’ that contains 8 darlington transistors similar in value to the BCX38C. The ‘chip’ also contains internal back emf suppression diodes and so no external 1N4001 diodes are required when driving motors and relays.

The ULN2803A is also called a 'low-side switch' - The load connects between the transistor output and V+ and the transistor conducts current to 0V when turned on.

Related Commands:

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Output via ULN2803A

This program outputs 8-bit data to the B.0 through B.7 pins which connect to an ULN2803A driver.

Code Example:
	dirsB = $FF		; Make B.0 to B.7 outputs

main:	for b0 = $00 to $FF
	  pinsB = b0		; Put binary value to B.0 to B.7
	  pause 250		; Wait a short while
	goto main		; Repeat
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Create Module

There is no specific ULN2803A create module but the BCX38C darlington transistor create modules may be used instead (shown connected to buzzer).

Bill of Materials

ULN2803A Darlington Driver ICO050 1 Buy Now
18-pin 0.3" DIL IC socket ICH018 1 Buy Now
100nF miniature polyester capacitor CAP001 1 Buy Now


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