14 Voltage Comparators, Timers, Counters

Describe the connection of each pin.

GND and VEE are connected to ground. VCC is connected to a positive voltage supply. Output is connected to VCC through a pull up resistor.

Describe the operation of the voltage comparator.

When VIN+ is higher than VIB-, the output transistor will switch off and act like an open switch/be disconnected from ground to provide a logic HIGH.

Describe the reset pin of a 555 timer

Reset resets the timing interval when connected to ground. The timer will not start again untl triggered by pin2. Connect to VCC when not in use

Describe the control pin of a 555 timer.

Controls the trigger and threshold level.

Describe the threshold pin of a 555 timer.

Monitors the voltae across the external capacitor. When the voltage in this pin reached 2/3VCC, the timing cycle ends and the output pin 3 goes to low.

Describe the trigger pin of a 555 timer.

Causes the output at pin 3 to go high and starts the timing cycle when its voltage drops below 1/3 VCC.

Describe the discharge pin of a 555 timer.

Connectd ti the ground and discharged the external capacitor connected to it when the output is LOW and acts like an opne circuit when the output is HIGH.

Describe the CKA pin.

It connects to a signal called clock, which increases the count value by one for every falling edge.

Describe the CLR pin

It connects to a signal called reset which resets the count value to zero when the input is HIGH.

Describe CKB pin

It connects to the QA pin which causes the counter to function as a decade counter.

Describe QA, QB, QC and QD pins

Combine together to represent the count value ad a binary coded decimal