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Ground them means connect them straight to ground, right? all the input & output pins?
for LM339, what do you mean ground one? one input? doesnt matter inverting or non-inverting?
what about the output pin of LM339? just leave it there?
thanks for the qucik reply.
Jack
hi everyone
i am building a small project that contains some logic ICs.
what should i do about the unused pins of those ICs?
the ICs are:
4027 dual J-K flip-flop (im only using 1 flip-flop)
LM339 quad voltage comparator (using 3 comparators)
4081 quad 2-input AND gate (using 2 gates)
i was...
firstly it is a TO220 package. and i am building a 100W 12VDC ---> 230VAC INVERTER.
here is my calculation, please correct me.
the max current is 8.333A (100W/12V)
the Rds(ON) is 0.27 (from datasheet)
max power dissipation is P = I2R = 18.75W
max junction temp Tj = 175deg C (from datasheet)...
hi guys, im trying to determine the heatsink for IRF520. according to the datasheet, i have calculated the Rth = 60 degree C/W, which the tutor said it didnt sound right.
the max current pass through is about 8.333A, and the ambient temp, i'd say 50 degree C?
can anyone help me with how to...
problem solved, the delay i had before was caused by the resistor i placed between "discharge" and "threshold". i re-do the whole circuit again without that resistor, and there is no deplay at all, or acceptable delay.
anyway, thanks all for the information.
thanks for the reply gusy, sorry about not posting enough information, i have been very busy attending lectures and breadboarding in the lab, havnt got much time to get on a computer. im going to re-connect the circuit and try different component values. i agree with FvM, ill try to post the...
ok, i used 555timer; 4027(dual J-K flip-flop); LM339(Quad voltage comparator); 4081(Quad 2-input AND gate). circuit is same as the circuit above, resistors and capacitors are used to get a 50Hz and 50% duty cycle. and i didnt terminate any unused pins. i asked the tutor he said its the delay of...
yes, i didnt save the waveform from the scope, ill do it tomorrow, and it is the Vcomp and Q¬Q out of phase, result the first & second transistor have different waveform form the graph above. ill try to describ it here and ill get the scope waveform later. the actual waveform i got is:
time...
there is a problem when i breadboard this circuit. there is a delay between the output of the comparator and the flipflop, which results the output of the ANDs are NOT what it suppose to be. is there any way to combat this problem?
exactly right. i think the whole purpose of this exercise is to get familar with the method of calculation and simulation software.
thanks all for the reply guys. it helps a lot with your experiances.
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