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inside a mains voltage touch-dimmer - with schematic
An interesting little module, but I would guess that its market has reduced greatly due to the unpredictable behaviour of LED bulbs with a phase angle control dimmer.
The radio geeks will NOT be impressed that this unit is using phase angle control with no filtering.
With this type of dimmer the bulb/lamp intensity control is achieved by varying the amount of the time the bulb is energised across the sinewave. A triac is used to control the load and by its design a triac will latch on and stay on until the current flowing through it drops to near zero. This allows very simple bulb intensity control by timing from the point the sinewave changes polarity (zero crossing point) and the point the triac is turned on in the sinewave. So for 50% power the triac would be turned on halfway through each half of the sinewave.
The chip is a dedicated one for this task. It has a zero crossing point detector and an adjustable oscillator/timer that is used to tune the unit to different frequencies like 50 or 60Hz.
I'm not convinced the touch input's capacitor is proper class Y, but at least it is a 3kV ceramic capacitor. I measured the touch sensor input to ground as passing 60uA. Other touch switches sometimes use a string of high value resistors to the touch plate.
Although these modules are only reliably suited to low power resistive loads like a tungsten bulb, you may still have use for one. So here's a link to the item on AliExpress (not a sponsor).
This is an affiliate link, but that will not affect the price you pay.
https://s.click.aliexpress.com/e/_c3yZcnwD
The unused capacitor position on the zero crossing point input could theoretically be used to introduce a slight phase shift to allow awkward loads like LED bulbs to pass enough current to latch the triac reliably. That could require tuning of the other timing resistor too.
If you enjoy my videos and would like to support me with a dollar or two for coffee, cookies and gadgets to take apart, you can do so by supporting me on Patreon. I release videos without adverts for critique and feedback on Patreon as soon as they have been made. I also release Patreon-only backstage videos when I'm working on shows.
https://www.patreon.com/bigclive
Alternatively, for a single coffee contribution you can use PayPal:-
https://www.paypal.com/paypalme/bigclive
#ElectronicsCreators
...
https://www.youtube.com/watch?v=J6cFAqZdzFw
The radio geeks will NOT be impressed that this unit is using phase angle control with no filtering.
With this type of dimmer the bulb/lamp intensity control is achieved by varying the amount of the time the bulb is energised across the sinewave. A triac is used to control the load and by its design a triac will latch on and stay on until the current flowing through it drops to near zero. This allows very simple bulb intensity control by timing from the point the sinewave changes polarity (zero crossing point) and the point the triac is turned on in the sinewave. So for 50% power the triac would be turned on halfway through each half of the sinewave.
The chip is a dedicated one for this task. It has a zero crossing point detector and an adjustable oscillator/timer that is used to tune the unit to different frequencies like 50 or 60Hz.
I'm not convinced the touch input's capacitor is proper class Y, but at least it is a 3kV ceramic capacitor. I measured the touch sensor input to ground as passing 60uA. Other touch switches sometimes use a string of high value resistors to the touch plate.
Although these modules are only reliably suited to low power resistive loads like a tungsten bulb, you may still have use for one. So here's a link to the item on AliExpress (not a sponsor).
This is an affiliate link, but that will not affect the price you pay.
https://s.click.aliexpress.com/e/_c3yZcnwD
The unused capacitor position on the zero crossing point input could theoretically be used to introduce a slight phase shift to allow awkward loads like LED bulbs to pass enough current to latch the triac reliably. That could require tuning of the other timing resistor too.
If you enjoy my videos and would like to support me with a dollar or two for coffee, cookies and gadgets to take apart, you can do so by supporting me on Patreon. I release videos without adverts for critique and feedback on Patreon as soon as they have been made. I also release Patreon-only backstage videos when I'm working on shows.
https://www.patreon.com/bigclive
Alternatively, for a single coffee contribution you can use PayPal:-
https://www.paypal.com/paypalme/bigclive
#ElectronicsCreators
...
https://www.youtube.com/watch?v=J6cFAqZdzFw
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By bigclivedotcomAn interesting little module, but I would guess that its market has reduced greatly due to the unpredictable behaviour of LED bulbs with a phase angle control dimmer.
The radio geeks will NOT be impressed that this unit is using phase angle control with no filtering.
With this type of dimmer the bulb/lamp intensity control is achieved by varying the amount of the time the bulb is energised across the sinewave. A triac is used to control the load and by its design a triac will latch on and stay on until the current flowing through it drops to near zero. This allows very simple bulb intensity control by timing from the point the sinewave changes polarity (zero crossing point) and the point the triac is turned on in the sinewave. So for 50% power the triac would be turned on halfway through each half of the sinewave.
The chip is a dedicated one for this task. It has a zero crossing point detector and an adjustable oscillator/timer that is used to tune the unit to different frequencies like 50 or 60Hz.
I'm not convinced the touch input's capacitor is proper class Y, but at least it is a 3kV ceramic capacitor. I measured the touch sensor input to ground as passing 60uA. Other touch switches sometimes use a string of high value resistors to the touch plate.
Although these modules are only reliably suited to low power resistive loads like a tungsten bulb, you may still have use for one. So here's a link to the item on AliExpress (not a sponsor).
This is an affiliate link, but that will not affect the price you pay.
https://s.click.aliexpress.com/e/_c3yZcnwD
The unused capacitor position on the zero crossing point input could theoretically be used to introduce a slight phase shift to allow awkward loads like LED bulbs to pass enough current to latch the triac reliably. That could require tuning of the other timing resistor too.
If you enjoy my videos and would like to support me with a dollar or two for coffee, cookies and gadgets to take apart, you can do so by supporting me on Patreon. I release videos without adverts for critique and feedback on Patreon as soon as they have been made. I also release Patreon-only backstage videos when I'm working on shows.
https://www.patreon.com/bigclive
Alternatively, for a single coffee contribution you can use PayPal:-
https://www.paypal.com/paypalme/bigclive
#ElectronicsCreators
...
https://www.youtube.com/watch?v=J6cFAqZdzFw
The radio geeks will NOT be impressed that this unit is using phase angle control with no filtering.
With this type of dimmer the bulb/lamp intensity control is achieved by varying the amount of the time the bulb is energised across the sinewave. A triac is used to control the load and by its design a triac will latch on and stay on until the current flowing through it drops to near zero. This allows very simple bulb intensity control by timing from the point the sinewave changes polarity (zero crossing point) and the point the triac is turned on in the sinewave. So for 50% power the triac would be turned on halfway through each half of the sinewave.
The chip is a dedicated one for this task. It has a zero crossing point detector and an adjustable oscillator/timer that is used to tune the unit to different frequencies like 50 or 60Hz.
I'm not convinced the touch input's capacitor is proper class Y, but at least it is a 3kV ceramic capacitor. I measured the touch sensor input to ground as passing 60uA. Other touch switches sometimes use a string of high value resistors to the touch plate.
Although these modules are only reliably suited to low power resistive loads like a tungsten bulb, you may still have use for one. So here's a link to the item on AliExpress (not a sponsor).
This is an affiliate link, but that will not affect the price you pay.
https://s.click.aliexpress.com/e/_c3yZcnwD
The unused capacitor position on the zero crossing point input could theoretically be used to introduce a slight phase shift to allow awkward loads like LED bulbs to pass enough current to latch the triac reliably. That could require tuning of the other timing resistor too.
If you enjoy my videos and would like to support me with a dollar or two for coffee, cookies and gadgets to take apart, you can do so by supporting me on Patreon. I release videos without adverts for critique and feedback on Patreon as soon as they have been made. I also release Patreon-only backstage videos when I'm working on shows.
https://www.patreon.com/bigclive
Alternatively, for a single coffee contribution you can use PayPal:-
https://www.paypal.com/paypalme/bigclive
#ElectronicsCreators
...
https://www.youtube.com/watch?v=J6cFAqZdzFw