Search found 148 matches

by vinod
Fri Nov 21, 2014 6:58 pm
Forum: Reader Projects
Topic: 40-pulses Monoshot (200ms/1A) design_help
Replies: 1
Views: 1659

40-pulses Monoshot (200ms/1A) design_help

Help me to design a Monoshot with the following specifications

1. 200ms pulse width
2. Magnitude 0.5V steps in 0-20V range (total 40 pulses). That is 0,0.5V, 1V, 1.5V,......,19.5V & 20V.
3. capacity to drive maximum 1A load.
by vinod
Sat Nov 01, 2014 10:09 pm
Forum: General Discussion
Topic: Electromechanical latching relay pull-in voltage
Replies: 4
Views: 888

Electromechanical latching relay pull-in voltage

We are using MIL standard Latching Electro-mechanical relays having dual ON/OFF coils. During screening process the relays are being subjected to pull-in voltage measurements for both ON & OFF coils in SRC (25 degree Celsius),COLD (8 degree Celsius) & HOT (80 degree Celsius) conditions. For pull-in ...
by vinod
Tue Oct 22, 2013 6:20 pm
Forum: General Discussion
Topic: Diode with floating terminal
Replies: 2
Views: 844

Re: Diode with floating terminal

with point A open, no current is flowing and you get the same voltage on both sides of the diode; 5V With point A loaded with a 10K load to ground, the short circuit current is ~500uA, with the diode forward resistance it will be a little lower but you will get a voltage corresponding to ~500uA on ...
by vinod
Tue Oct 22, 2013 10:07 am
Forum: General Discussion
Topic: Diode with floating terminal
Replies: 2
Views: 844

Diode with floating terminal

Consider the circuit arrangement shown in the attachment.
If I connect a MM in voltmeter mode at floating terminal A, What would be the reading on the voltmeter?
If I terminate the floating A terminal with a 10K resistor to GND, What would be the change in reading shown?
by vinod
Fri Oct 11, 2013 9:30 pm
Forum: General Discussion
Topic: Diode forward/reverse resistance measurement
Replies: 4
Views: 1335

Diode forward/reverse resistance measurement

See the diagrams attached herewith. Diode Diode arrangement DFR- Diode Forward Resistance DRR- Diode Reverse Resistance Both are identical diodes and the multimeter is set in auto range(resistance mode). MM shows 43M Ohm instead of OL! ( If I connect a multimeter positive terminal at A & negative te...
by vinod
Mon Aug 19, 2013 11:03 am
Forum: General Discussion
Topic: Diode ORing voltage measurement
Replies: 4
Views: 1578

Diode ORing voltage measurement

For the below circuit, I have placed multimeter +ve probe at 'B' wrt GND and measures 4V against the expected value of 0V. Hence I have terminated the 'B' end with 10K to GND temporarily before taking the measurement and reads 0V. Why this happens? What happens to the anode of D2 while I connect a m...
by vinod
Mon Mar 04, 2013 4:51 pm
Forum: General Discussion
Topic: Voltage Drop measurement using Multimeter in a 5A live line
Replies: 4
Views: 1151

Re: Resistance/Voltage measurement using multimeter

sghioto wrote:This doesn't make any sense. How do you expect to calculate the voltage if you don't know the values of the resistors. :???:
Sorry, I have modified my post, It was a mistake --I want to measure voltage drop.
by vinod
Mon Mar 04, 2013 8:42 am
Forum: General Discussion
Topic: Voltage Drop measurement using Multimeter in a 5A live line
Replies: 4
Views: 1151

Voltage Drop measurement using Multimeter in a 5A live line

Consider the below circuit with 28V supply and electronic load set at 5A Constant Current mode. What voltage drop would I expect when I connect a digital multimeter between A & B ? V(AB1)= V(R6)+V(R8)+V(R9) What voltage drop would I expect when I connect a digital multimeter between C & D ? V(CD1)= ...
by vinod
Mon Mar 04, 2013 6:34 am
Forum: General Discussion
Topic: 4047 monoshot(1ms pulse width)
Replies: 13
Views: 2200

Re: 4047 monoshot(1ms pulse width)

Yes! Steve G I'm afraid that the very low discharge time(0.01ms) will lose the function of debounce(as bounces lasts for some time after releasing the switch- from NO to NC). Can I solve the problem by swapping 100 Ohm & 100K ? But it will increases the minimum time required for keeping the switch ...
by vinod
Sun Mar 03, 2013 4:53 pm
Forum: General Discussion
Topic: 4047 monoshot(1ms pulse width)
Replies: 13
Views: 2200

-ve edge triggering during switch pushing

OK but I would reverse the connections on the switch. A pulse will generate only when the trigger is released unless that's OK. Steve G Do you mean this type of arrangement so that triggering happens when the switch is pressed not 'released' ? :idea: It has an added advantage that the minimum time ...
by vinod
Sun Mar 03, 2013 6:41 am
Forum: General Discussion
Topic: 4047 monoshot(1ms pulse width)
Replies: 13
Views: 2200

Re: 4047 monoshot(1ms pulse width)

Now's the time to build the circuit and see if it works as designed. Steve G As per my friends opinion the debounce circuit has a slow rise time and fast fall time, so would best be used for triggering the -T rather than the +T pin of the mono. Hence I simply change the trigger line from 8th pin to...
by vinod
Sun Mar 03, 2013 1:18 am
Forum: General Discussion
Topic: 4047 monoshot(1ms pulse width)
Replies: 13
Views: 2200

output drive with debouncer

Here is another arrangement with output drive and debouncer.
by vinod
Sat Mar 02, 2013 6:49 pm
Forum: General Discussion
Topic: 4047 monoshot(1ms pulse width)
Replies: 13
Views: 2200

Re: 4047 monoshot(1ms pulse width)

The actual delay will depend on the minimum value of input voltage required to trigger the 4047. At 5 volts Vcc the typical value is 2.25 volts to trigger at 25 degrees celcius. So it will take C4 apprx 7ms to charge to that value. Remember a lot of this depends on the switch itself and how much bo...
by vinod
Sat Mar 02, 2013 10:10 am
Forum: General Discussion
Topic: 4047 monoshot(1ms pulse width)
Replies: 13
Views: 2200

Re: 4047 monoshot(1ms pulse width)

Oh wow! Here we go again. :) You can see the 1ms pulse on a LED if the LED is in the off mode. However because the green LED is normally on you won't see it turn off because of persistence of vision. The trigger circuit is designed to incorporate a slight delay ( about 10ms ) when activated and pre...
by vinod
Sat Mar 02, 2013 4:34 am
Forum: General Discussion
Topic: 4047 monoshot(1ms pulse width)
Replies: 13
Views: 2200

4047 monoshot(1ms pulse width)

I have designed oneshot for 1ms Pulse width using 4047. R5- makes output current >= 10mA to ensure load regulation. C4- prevents bouncing of trigger switch. 1N4002- prevents discharging of c1 through LM317T. 1. Is it possible to see the 1ms ' short time ' switching between RED & GREEN LEDs at output...