Can I use an H-bridge chip to accomplish this? If I wanted to do a square wave to approximate a 24VAC output, would I use 34V and negative 34V? Or would I use 24V and negative 24V?
These are the H-bridge chips I was looking at:
DRV8251DDAR...
24VAC Valves only - no DC valves. On the more rare occurance it will power 24VAC relays, and control HVAC devices that require 24VAC signals to operate. Sure, some of the things "might" work with 24VDC. Technically they can put whatever they want on the power source, so long as it doesn't...
Solenoids are not the only thing that its going to power. 90% of the time it will be solenoids. It has to be 24VAC output. Yes it is a lot of effort but it has to be done, there is no way around this requirement.
I've already suggested this to everyone that this is simpler - everyone hates the look of a massive transformer and is absolutely not going to work for this. It has to be a 120V plug (C8 plug receptacle), and it has to be small.
There is a power module on the circuit board that receives 120VAC and converts it to 36VDC. You need 34VDC to create the peaks of 24VAC. I have to create a 24VAC output. DC output is not an option.
I want to use this to drive rainbird sprinkler valves. Ideally the output would be sinewave if I can pull that off - but technically they run ok with a 24VA squarewave as well. Either will work. I want to incorporate it into a PCB to just use raw components.
Hello, I am wanting to generate a 24VAC output, and be able to put up to a 2 amp load on it. The available power is 36VDC or 40VDC (3 or 4 amp). No transformer - this has to be generated off the main DC voltage.
As we know, a 24VAC output consists of a sinewave with a peak voltage of +34VDC and...
Thanks again for the response. That chart in my initial posting has the capacitance values involved. Completely dry reading is under 100pF. A little bit of water is around 11.5nF. Pretty wet is closer to 10uF, and fully saturated is around 15uF.
Thanks again for the response! Resistance based sensors, or circuits that measure EC (electrical conductivity) is popular, but they are drastically effected by the salinity of the soil. The capacitance based method is supposed to be the more "accurate" way of measuring soil moisture as salinity...
Thanks for the response! Are you suggesting doing something like this? I didn't put the LED's in the mix, because in the end I still need to read an analog value to determine the capacitance: e.g. run the analog value into an ADC and do a calculation.
Thank you as well for the response! The...
I came across this circuit that measures capacitance mainly between 30pF and 300pF, and is typically used between 31KHz and 250KHz. It basically outputs a 0-5V analog value that correlates with the capacitance. I drew a green arrow pointing to where the measurement is taking place. Its basically...
Hey guys, so I did get a chance to try this out. I ran each phase through a 51K resistor and through an opto-coupler (part # TLP290-4(GB-TP,E) ). The optocoupler, paired up with a capacitor and a pull down resistor generates a nice clean 0V for "phase disconnected" and a 3.15V for "phase...
Would it be best to use the opto IC's across the breaker, so if the breaker trips, the opto IC would start conducting.
Or would it be better to use the opto on just one side of the breaker along with a neutral. This would start conducting immediately and would stop as soon as the breaker trips.
To answer some of the questions and to clarify - the main breaker box contains a proper 3-phase circuit breaker. Its my device that contains the relays and a much lower amperage circuit breaker for further protection. This part is mainly to protect the traces on the circuit board from excessive...