Howdy all,
I'm trying to switch an AC Sprinkler Solenoid using a MAC97A6 Triac using a microcontroller.
I tried with the AC Adapter running through full wave bridge rectifier then into LM2596 based buck converter module (cheap eBay module) to get 5V (end up with about 38V after the rectifier and nice clean 5V after the buck converter).
It works fine if I short the Gate of the Triac to the +5V rail via a 470R resister, but if the microcontroller or a 74HC04 Hex Inverter drives the Triac, it goes On then rattles on-and-off at 50Hz in the Off state.
On the scope, I get nearly 80V point-to-point on the Gate of the triac (on both sides of the resister) so I guess that's the issue.
I also tried with a half wave rectifier (just a 1N4004 diode) and got the same result (not surprisingly I guess because the AC, which is almost 80V Point-to-point, is still running to the solenoid).
So my two questions are:
1. Why does it work if I short to +5V but not via the microcontroller or Hex Inverter?
2. How do I get the microcontroller to reliably switch the AC for the Solenoid using this Triac?
Thanks,
David
I'm trying to switch an AC Sprinkler Solenoid using a MAC97A6 Triac using a microcontroller.
I tried with the AC Adapter running through full wave bridge rectifier then into LM2596 based buck converter module (cheap eBay module) to get 5V (end up with about 38V after the rectifier and nice clean 5V after the buck converter).
It works fine if I short the Gate of the Triac to the +5V rail via a 470R resister, but if the microcontroller or a 74HC04 Hex Inverter drives the Triac, it goes On then rattles on-and-off at 50Hz in the Off state.
On the scope, I get nearly 80V point-to-point on the Gate of the triac (on both sides of the resister) so I guess that's the issue.
I also tried with a half wave rectifier (just a 1N4004 diode) and got the same result (not surprisingly I guess because the AC, which is almost 80V Point-to-point, is still running to the solenoid).
So my two questions are:
1. Why does it work if I short to +5V but not via the microcontroller or Hex Inverter?
2. How do I get the microcontroller to reliably switch the AC for the Solenoid using this Triac?
Thanks,
David