Ground triggered Latching Circuit using transistors

dl324

Joined Mar 30, 2015
15,475
I'm utilizing Alex_t recommendation in post 128.

Grounded pins 8,9,10,11 ... and added the transistor and led on post 168.

It works on my sim .... not on my breadboard.
I was just going to say I thought you were using a negative trigger when you updated your post...

As others have mentioned, it may be noise from switching the relay. Try replacing the relay coil with a resistive load. If that fixes the problem, it's a wiring/supply decoupling issue.
 

Alec_t

Joined Sep 17, 2013
13,232
Did you replace the low value resistor with a 10k on the transistor base?
There's a possibility that, with a 12V supply and only 100Ω (or less) effectively 'shorting' the Q output to ground, the IC was damaged. Static electricity is also a killer of CMOS circuits such as the 4013.
 

Thread Starter

stillgrowingup

Joined Jul 15, 2015
210
Did you replace the low value resistor with a 10k on the transistor base?
There's a possibility that, with a 12V supply and only 100Ω (or less) effectively 'shorting' the Q output to ground, the IC was damaged. Static electricity is also a killer of CMOS circuits such as the 4013.

I did swap out the resistor with a 10k, 33k, 50k, 100k, 200k and 300k. Did not toggle.

But ..... when I turned off my power supply, I was pressing the PB as my power supply was fading. It DID toggle when the voltage got to 3.5v. I was able to reproduce that each time the I turned off the power supply, no matter what the resistor value was on the 4013 output to transistor.

At this point, I too am wondering of the 4013 is bad. :( ... I have 2 of a CD4075BE cmos. That's not the same, is it?

Tony

Update: I have ordered 5 more 4013 chips ... and 5 ULN2004 :) . Should be here by end of week.
 
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Thread Starter

stillgrowingup

Joined Jul 15, 2015
210
Thank you guys for ALL your advice and input. :)

HI:)

I hope no one minds me jumping in here but I have suggestion..:)

Why not use a ULN2004 to drive the loads?

See attached...I've only shown the graphic for one of the lamp circuits but they would both be the same.
I got the new 4013 and ULN2004 in today and your circuit worked on my Breadboard, thank you. I used 100nF for all 4 circuit capacitors, because that is all I had.

I looked at the datasheet for the ULN2004. It appears to be limited to 500mA per output channel. Correct?

I do not see 500mA being a problem, just want to confirm.
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@Alec_t .. I tried your circuit (post #132) with the new 4013. I grounded pins 8, 9, 10 and 11 and I add a 2N3904 on the 4013 output for the LED and relay. It still did NOT toggle, but did toggle when the breadboard voltage was between 3v-3.5v ... This makes no sense to me because the full circuit I posted in #136, which is a marriage of yours circuits in post #117 & #132, did work ... sorta. It didn't always toggle. I had to change the resistor values of R3, R5, R7 and R11 from 330k to 100k.

I have attached the updated working schematic with the value changes below.

TONY

4013 Working.JPG
 
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eetech00

Joined Jun 8, 2013
3,418
Thank you guys for ALL your advice and input. :)

I got the new 4013 and ULN2004 in today and your circuit worked on my Breadboard, thank you. I used 100nF for all 4 circuit capacitors, because that is all I had.

I looked at the datasheet for the ULN2004. It appears to be limited to 500mA per output channel. Correct?

I do not see 500mA being a problem, just want to confirm.
Hi...glad it worked out.

The recommended current output per channel depends on how many channels are being used at the same time, how long each channel is on (duty cycle), and the chip package. It also depends on the chip manufacture. The TI chip datasheet has a couple of charts that show output current vs duty cycle. On continuously is 100 percent duty cycle.
The chips you bought are made by which chip manufacturer?

I think you can get about 100-140ma per channel if all channels on simultaneously. Its all about how cool they operate.
You can also parallel the chips to get more current.
 

Thread Starter

stillgrowingup

Joined Jul 15, 2015
210
@Alec_t ... Thank you for sticking with me! :)


@eetech00 ... I have ST Micro 2004 chip drivers. I looked on the datasheet offered through mouser and I did NOT see a 100% duty cycle specifications.
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My ultimate circuit would have (2) 4013. Each output would need to trigger 1 relay (16mA), 1 LED (10mA) and one 3 Watt bulb (250mA). LED and Relay would share 1 output (26mA total). If I was to use the ULN2004, that would leave me with 3 Uln2004 outputs left and I need 4. Each with a max rating of 250mA for the bulbs and the chip can only handle 100-150mA each output. :( .... So if this was to work, I would have to have (2) 4013 and (2) 2004 and share 2004 outputs.

Now if I go with the BD139 per 4013 output. There will be more PCB Components, but I'll have 1.5A max per 4013 output, which is enough to handle the Bulb, LED and relay.

So is the safe bet to go with the BD139 output, NOT the ULN2004?

TONY
 
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eetech00

Joined Jun 8, 2013
3,418
@Alec_t ... Thank you for sticking with me! :)


@eetech00 ... I have ST Micro 2004 chip drivers. I looked on the datasheet offered through mouser and I did NOT see a 100% duty cycle specifications.
------------------
My ultimate circuit would have (2) 4013. Each output would need to trigger 1 relay (16mA), 1 LED (10mA) and one 3 Watt bulb (250mA). LED and Relay would share 1 output (26mA total). If I was to use the ULN2004, that would leave me with 3 Uln2004 outputs left and I need 4. Each with a max rating of 250mA for the bulbs and the chip can only handle 100-150mA each output. :( .... So if this was to work, I would have to have (2) 4013 and (2) 2004 and share 2004 outputs.

Now if I go with the BD139 per 4013 output. There will be more PCB Components, but I'll have 1.5A max per 4013 output, which is enough to handle the Bulb, LED and relay.


So is the safe bet to go with the BD139 output, NOT the ULN2004?

TONY

Hi

Check the STMicro datasheet, FIG 17,18:
http://www2.st.com/content/ccc/reso...df/jcr:content/translations/en.CD00001244.pdf
The charts show the current vs Duty cycle. Use the line in the horizontal axis labeled "DC".
Each output is capable of 500mA, but your only using two of the outputs at 250ma each and two outputs at 26mA each. So total for the chip is about 552mA. This should be ok..
 
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Thread Starter

stillgrowingup

Joined Jul 15, 2015
210
For a high current load, the base current for a BD139 would be more than the 4013 could provide directly, so you would need to drive the BD139 base with another transistor.
So the 4013 could NOT supply enough saturation to the BD139? That must be why the circuit in post #187 works. The 4013 output is driving a 2N3904 to drive Base current of the BD139. .. Cause the 4013 output to directly drive the an BD139 didn't work. Even though both of our SIMs said it would work, it didn't :(

I'm so happy this works now. :)

TONY
 

eetech00

Joined Jun 8, 2013
3,418
Hi

Just as an FYI.

I tested a ULN2003a (didn't have a 2004) with a continuous 15v@600mA load (300ma on two separate pins).
I used 5v to drive the inputs. I measured the chip temperature with a laser temp gun for about 30 minutes.
The temp averaged about 36 degrees C.

The chip was warm (close to hot) to the touch but didn't burn.

I don't think I'd load this chip with more current then this without a heat sink.
 

Thread Starter

stillgrowingup

Joined Jul 15, 2015
210
Hi

Just as an FYI.

I tested a ULN2003a (didn't have a 2004) with a continuous 15v@600mA load (300ma on two separate pins).
I used 5v to drive the inputs. I measured the chip temperature with a laser temp gun for about 30 minutes.
The temp averaged about 36 degrees C.

The chip was warm (close to hot) to the touch but didn't burn.

I don't think I'd load this chip with more current then this without a heat sink.
Thank you for the valuable info :)

They make heat sinks for IC chips? ... I didn't know :)

Tony
 
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