I have a clock, based upon a NE555 oscillator, with its pin 3 (Q) being fed into a pin 1 of CD4069

However the signal from output of pin 2 of the CD4069 is incorrect.

Pin 1 input = 0 volt the output of Pin 2 = 10 volts (which is correct)
however when
Pin 1 input = 10 volts the output of Pin 2 = 10 volts (which is incorrect, as it should be inverted ie 0 volts)

Very basic logic.

I have changed CD4069 3 times with new chips, but they are all the same.

Do I assume I have a bad batch ? from Aliexpress.

Any advice would be gratefully received.

 

What is the 555 freq?
The freq might be fast enough for the 4069 output to appear constantly high.

as a test, disconnect the 555 output from the 4069 and try manuallly jumperimg the 4069 input both low then high while monitoring the output to check the 4069 output is changing state.

 

I have a clock, based upon a NE555 oscillator, with its pin 3 (Q) being fed into a pin 1 of CD4069

However the signal from output of pin 2 of the CD4069 is incorrect.

Pin 1 input = 0 volt the output of Pin 2 = 10 volts (which is correct)
however when
Pin 1 input = 10 volts the output of Pin 2 = 10 volts (which is incorrect, as it should be inverted ie 0 volts)

Very basic logic.

I have changed CD4049 3 times with new chips, but they are all the same.

Do I assume I have a bad batch ? from Aliexpress.

Any advice would be gratefully received.

Are the other, unused inputs of the 4069 grounded? If left floating you can expect to see strange behavior sometimes, probably not the cause of your problem but not something to disregard.

 

CD4049 and CD4069 do not have the same pinout. For one thing, CD4049 has 16 pins. CD4069 has 14 pins.

 

Yea, I would be very suspect of the chips.

(Assuming your testing method is correct)

 

The only way to discuss problems with a circuit is for everyone to see the circuit. Please post a schematic of *your* circuit (not a copy of an internet image). Show every connection to every pin, including power connections, and label each part with a unique reference designator and component value. It doesn't have to be pretty, just accurate.

ak

 

I have changed CD4049 3 times with new chips, but they are all the same.

CD4069 or CD4049? They're different chips.

Do I assume I have a bad batch ? from Aliexpress.

Maybe. Were they package properly (in antistatic material)? Were they handled properly (ESD strap)?

 

CD4049 and CD4069 do not have the same pinout. For one thing, CD4049 has 16 pins. CD4069 has 14 pins.

View attachment 358127

View attachment 358129

I did have to check a number of times, just in case I had got it wrong. But CD4069 is correct, and I have changed original post.

Thanks for pointing it out.

 

CD4069 or CD4049? They're different chips.
Maybe. Were they package properly (in antistatic material)? Were they handled properly (ESD strap)?

They came in a normal plastic tube, cut in half to fit the packaging. And sealed with tape to stop them from falling out.

I have ordered new ones, so I have to wait a few days. Will try out some suggestions in the meantime.

 

What is the 555 freq?
The freq might be fast enough for the 4069 output to appear constantly high.

as a test, disconnect the 555 output from the 4069 and try manuallly jumperimg the 4069 input both low then high while monitoring the output to check the 4069 output is changing state.

The NE555 is running at 1 cycle every 60 secs (30 secs on and 30 secs off). So very slow.

Your other suggestion, I will try tomorrow.

I have tried using the next inverter down ie pins 3 and 4 and I get the same results.

Noticed that the NE555's supplied are in fact 7555. Which should be better.

 

I have a clock, based upon a NE555 oscillator, with its pin 3 (Q) being fed into a pin 1 of CD4069

However the signal from output of pin 2 of the CD4069 is incorrect.

Pin 1 input = 0 volt the output of Pin 2 = 10 volts (which is correct)
however when
Pin 1 input = 10 volts the output of Pin 2 = 10 volts (which is incorrect, as it should be inverted ie 0 volts)

Very basic logic.

I have changed CD4069 3 times with new chips, but they are all the same.

Do I assume I have a bad batch ? from Aliexpress.

Any advice would be gratefully received.

Please check the datasheet and make sure that you are doing everything right (Giving the correct supply voltage, current etc.) Also check for faults in your connection and the quality of connecting wires.

 

It sounds like you have no GND connection on pin-7.
Check with a voltmeter. Measure the voltage from PSU GND to CD4069 pin-7 (actually probe pin-7 on the chip itself).

 

They came in a normal plastic tube, cut in half to fit the packaging. And sealed with tape to stop them from falling out.

Are you handling them properly?

 

I have a clock, based upon a NE555 oscillator, with its pin 3 (Q) being fed into a pin 1 of CD4069

However the signal from output of pin 2 of the CD4069 is incorrect.

Pin 1 input = 0 volt the output of Pin 2 = 10 volts (which is correct)
however when
Pin 1 input = 10 volts the output of Pin 2 = 10 volts (which is incorrect, as it should be inverted ie 0 volts)

Very basic logic.

I have changed CD4069 3 times with new chips, but they are all the same.

Do I assume I have a bad batch ? from Aliexpress.

Any advice would be gratefully received.

To better help you, please post both a schematic, even hand sketched, of the circuit as you intended to wire it up, and also a picture of how it is actually wired up. Make sure that we can follow the connections in the picture (take multiple pictures from different angles, if necessary).

Be sure that your power and ground connections are correct.

Be sure that the 555 and the 4069 have the same ground reference.

Be sure that unused inputs are tied to a valid logic level and that unused outputs are left floating. An easy way to do this is to tie the inputs on one side to Vdd and the inputs on the other to GND. This also lets you do a quick sanity check by seeing in the outputs on the first side are all LO and that they are all HI on the other side. If not, then you have more fundamental problems that need to be addressed.

If it does turn out that the chips are bad, ask yourself if the money you saved by buying from Aliexpress was enough to compensate you for the aggravation that results, not to mention the lost time and the need to now buy another set of chips.

 

Just for info, schematic as below. Do not worry about the values of timing C1, R13 (R1), R12 (R2) as they have changed.

J4 and J5 just bring out the pins of 2 inverters, in case I need to incorporate a time delay.

 

Hello,

Remove the leds D5 and D14.
Also remove R1 and R15.
Those components will interfere with the voltage levels at the gates of the mosfets.

Bertus

 

Do not drive an LED and other circuits from the same output.
An LED must be driven by its own buffer. Don't try to tap off another signal from this buffer.

 

Remove R13 and R25. The are not needed.
Operate the circuit with 12v supply.
Any LED connected to an inverter output must not draw more than 2-3mA, so they will need to be low current high efficiency LEDs.
If more LED drive current is needed:
Operate each LED with a dedicated transistor driver
Or operate each LED with two 4069's connected in parallel for more output current.

 

As mentioned earlier unused input pins 9,11 and 13 should be connected to +Vcc. or negative/ground.
Input pins 3 and 5 need a pull down resistor.

 

As mentioned earlier unused input pins 9,11 and 13 should be connected to +Vcc. or negative/ground.
Input pins 3 and 5 need a pull down resistor.

Hi - I understand re pins 9, 11 and 13.

But can you explain further using pull down resistors and also if possible, a circuit showing their use or a link to a typical diagram