Just a quick question on 4093bp ICs

[bigal_scorpio]

Hi to all, just wondered if anyone can explain to me how to check if a TC4093bp Ic is ok, I don't have any experience in testing ICs, trannies were my limit in testing savvy

Any help will be greatly appreciated as I have built a circuit that as usual doesn't work and checked all the circuit over and over

As I mentioned in another thread all the ICs I have were donated to me and I cant say what their condition is, thats the trouble with electronics, the little buggers can look fine and be dead as dodos!

All I have test wise is a digital multimeter, but at least its a decent one I think, so anyone who knows about testing 4093 ICs please give me a shout.

Thanks in advance.............Al

 

[audioguru]

You forgot to attach your schematic.
You forgot to say what goes wrong.

A 4093 is a Cmos quad NAND gate with Schmitt-trigger inputs.
If either or both inputs are low, the output will be high.
If both inputs are high then the output will be low.
With a 5V supply its output can source or sink up to about 2mA.
With a 10V supply its output can source or sink up to about 10ma.

 

[bigal_scorpio]

Oops! forgot the diagram

You forgot to attach your schematic.
You forgot to say what goes wrong.

A 4093 is a Cmos quad NAND gate with Schmitt-trigger inputs.
If either or both inputs are low, the output will be high.
If both inputs are high then the output will be low.
With a 5V supply its output can source or sink up to about 2mA.
With a 10V supply its output can source or sink up to about 10ma.

Here is the diagram, sorry about forgetting it, think it must be frustration of circuit death though I should be used to it by now

As to the problem with the circuit, it just doesn't work.

I'm using it on a 9v battery, and as testing goes I wondered if it was possible to measure the IC out of circuit?

I may have killed the 2 I tried in so far and am running out fast, so if poss I would like to test one I have used already without bringing the circuits possible faults into the equation, can it be done and if so by what method could I test the chip?

Thanks again in advance.........Al

 

[audioguru]

The circuit looks fine.
What is wrong?
Does it pip-pip-pip... when a gate is opened?
Does it pip for 20 to 30 times after the gate is closed?

 

[bigal_scorpio]

Further developements

The circuit looks fine.
What is wrong?
Does it pip-pip-pip... when a gate is opened?
Does it pip for 20 to 30 times after the gate is closed?

It does absolutely nothing, not even that oh so familiar burning smell

I even substituted an LED for the Piezo disc as the Rev Scarborough says in the text that comes with the diagram, but not a blink!

 

[audioguru]

An LED on the output replacing the piezo transducer should blink dimmly when a switch is turned on. The LED won't light if it is connected backwards.

Try connecting the piezo transducer to pin 3 and ground. It should make a continuous tone. The pitch should be able to be changed with adjusting the trimmer resistor.
Try connecting an LED from pin 4 to ground in series with a 10k resistor. It should blink very dimmly.
Try connecting an LED from pin 10 to ground It should blink dimmly.
Try connecting the piezo transducer to pin 10 and ground. It should pip-pip-pip continuously.

The 10nF capacitor is 0.01uF. The 22k trimmer resistor is an unusual value, it could be a 20k trimmer in series with a 2.2k resistor or it could be a 50k trimmer. Measure the resistance of the trimmer to see if it can be adjusted from about 10k to 22k ohms.

 

[bigal_scorpio]

Further testing of circuit

An LED on the output replacing the piezo transducer should blink dimmly when a switch is turned on. The LED won't light if it is connected backwards.

Try connecting the piezo transducer to pin 3 and ground. It should make a continuous tone. The pitch should be able to be changed with adjusting the trimmer resistor.
Try connecting an LED from pin 4 to ground in series with a 10k resistor. It should blink very dimmly.
Try connecting an LED from pin 10 to ground It should blink dimmly.
Try connecting the piezo transducer to pin 10 and ground. It should pip-pip-pip continuously.

The 10nF capacitor is 0.01uF. The 22k trimmer resistor is an unusual value, it could be a 20k trimmer in series with a 2.2k resistor or it could be a 50k trimmer. Measure the resistance of the trimmer to see if it can be adjusted from about 10k to 22k ohms.

Thanks for the quick response.

piezo transducer to pin 3 and ground = No effect
piezo transducer to pin 10 and ground = No effect
LED from pin 4 to ground through 10k = Still Nothing
LED from pin 10 to ground through 10k = Still Nothing

VR1 is a 22k trimmer ( I have some old and strange values!) its NOS and tests ok.

Can I actually measure any of the IC pins with the meter (out of circuit) to determine if its ok? If so what range would be safe or applicable. Or maybe logic ICs can't be measured this way?

Thanks again Audioguru or should I call you Uncle Scrooge?.........Al

 

[mvs sarma]

Hi Bigal_scorpio,

Try to put a photo of your assembly, both sides if it is PCB, or top side if breadboard-- Most probably you might have given connctions wrongly--

I suggest , keep it aside and wire another afresh without looking at old one., don't try to debug-- once it works you can compare and trace the mistake.

you need to have feww test accessoried for debugging it.
1. a transistor with emitter earthed, base with series 10K,other side extended witha wire to any point you wanto test-- collector connected with a RED LED witha 1K series resistor to the +9V as you said--you may call this a temporary probe.

once you have this and a breadboard, you can test each logic gate independently. it will also help tracing the circuit later.

 

[kchriste]

You can do this to IC1 in circuit:
Bridge pins 1&2 to ground and pin 3 should go to near 9V.
Bridge pins 1&2 to +9V line and pin 3 should go to near 0V and pin 10 should go to near 9V.
Bridge pins 5&6 to ground and pin 4 should go to near 9V.
Bridge pins 5&6 to +9V line and pin 4 should go to near 0V and pin 10 should go to near 9V.
Bridge pins 1,2,5&6 to ground and pin 10 should go to near 0V.
Turn SW1 on and then bridge pins 1,2,5&6 to +9V and pin 10 should go to near 9V and pin 11 should go to near 0V. Turning SW1 on and off (With all other switches off) should toggle the voltage at pin 11 between 0 and 9V while pins 1,2,5&6 are bridged to +9V.
This is a simple check. It won't find all the possible faults with IC1 but it will identify the most common.

 

[bigal_scorpio]

Yipee!

At last! Its working, with the help from all you out there!

Well when I say its working:confused

It now seems to be doing what it should, but very very quietly.

Are there different types of piezo disc? Mine are just brass coloured 10p size wafers with a smaller wafer on one side.

Or could I use a transistor to amp up the output to the piezo? Say a 2n3904 and use the piezo output to the base and collector to ground and emitter to the disc, then the other connection on the disc to pos 9v?

Thanks for all the help, I am already forever in everyones debt.

Al

 

[kchriste]

Try tuning VR1 first. Piezo's have a resonant frequency and to be loud they must be driven at the proper frequency.

 

[bigal_scorpio]

Whooooopeeee

Hi folks,

Got the volume problem sorted, swapped the VR1 22k for a 100k trimmer and its like a revelation, plenty loud now, have to cover my ears!

Anyway I was really glad of all the help and hope one day I can return the favours. If anyone needs any old weird parts, old ICs or bits off satellite receivers just let me know, and I'll try my best to help.

Thanks again............Al

 

[audioguru]

I have a bare piezo transducer that is not loud. Then I held it near a deep bottle cap and it makes a resonant cavity which makes it very loud. I also have a piezo that comes in a black plastic resonant chamber that is loud at a certain frequency.