Problem With a counter

[saeed_pk]

cunter 74190 circuit

Hi All,
I m miaking a counter with 74LS190 but having problems when i make the circuit on the Data sheet (Motorola) I am confused what to do with Parallel load/input pins and their enable .
this is a counter that counts from 0-9
and what happens if i left unused pins open
plz tell me whether this ciruit is right or if u have any other suggestion like different IC ( Please give circuit too)
Thanx All
Bye

 

[konarkk]

1st u check that the IC u Used is TTL or CMOS .
If IC is CMOS then grounding an unused pins , otherwise IC burnt out.
further I can give u a guideline after anlysing a counter, till then bye.

 

[Ave_Rapina]

In any cmos circuit you should have any input in the air becouse it becomes an antena and destroy the device.
If you dont want any parallel load you shoul put the /Pl pin to an high level using an resistor for example 4.7K
The inputs of paralel load bit must be grounded
/Ce must be at low leve for the counter run
Regards

 

[yogi]

better not to keep the 74190 pins open, it will count in an unusual way.