24 Volt Transformer, 40 VA AC Transformer Plug in with PTC Fuse Compatible with Ring Doorbell and Thermostat, Compatible with Nest, Ecobee, Sensi/Honeywell/ 24V Adapter (1 Pack)
Condition: New
Buy Now, Pay Later
As low as
$4
/ mo
Learn more
- – 4-month term
- – No impact on credit to apply
- – Instant approval decision
- – Secure and straightforward checkout
Ready to go? Add this product to your cart and select a plan during checkout.
Payment plans are offered through our trusted finance partners Klarna, Affirm, Afterpay, Apple Pay, and PayTomorrow. No-credit-needed leasing options through Acima may also be available at checkout.
Learn more about financing & leasing here.
Selected Option
Free shipping on this product
30-day returns
Learn more
FREE 30-day refund/replacement
To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
Availability:
In Stock.
Arrives
Wednesday, Mar 25
Recently Viewed
Number of Items: 1
Features
- Eliminate doorbell/ thermostat underpower hassle: 24V 40VA plug-in transformer replaces and upgrades underpowered transformer with this 24V AC transformer
- Specification: input voltage: 120 VAC, 60Hz; Output voltage: 24V, 40VA
- Safe and stable: auto-resetting (PTC) fused secondary, LED green power indicator, positive/ negative/ screw terminals
- Universal compatibility: this 24v transformer is compatible with Ring Video Doorbell, Ring Video Doorbell 2, Ring Video Doorbell Pro, Nest Skybell doorbell
- Also compatible with Nest, Ecobee, Honeywell, and Sensi smart thermostats, and other devices that require constant 24-volt power for operation;
Brand: Hotop
Power Source: Corded Electric
Product Dimensions: 2.13"D x 2.56"W x 3.94"H
Mounting Type: Wall Mount
Current Rating: 1.5 Amps
Specification Met: UL
Item Weight: 1.6 Pounds
UPC: 796168988969
Manufacturer: Hotop
Product Dimensions: 2.13 x 2.56 x 3.94 inches
Item Weight: 1.61 pounds
Item model number: PS D40
Date First Available: January 11, 2020
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Wednesday, Mar 25
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
- Klarna Financing
- Affirm Pay in 4
- Affirm Financing
- Afterpay Financing
- PayTomorrow Financing
- Financing through Apple Pay
Learn more about financing & leasing here.
Similar Products
Top Amazon Reviews
Number of Items: 1
Got this transformer to replace an older 16V transformer in my house as I needed up upgrade for a Tapo doorbell unit I received recently. I bought this transformer and a replacement 24V doorbell chime. This transformer seems to work well and performs as expected. Other reviews state that this transformer outputs higher than 24vac. Yes, that’s true but it’s on purpose. There is no regulation on these. It’s a straight step down transformer. The higher voltage will drop for two reasons. 1) current draw (load) and 2) cable run (length). Both of these things have a greater effect on voltage drop than a regulated power supply would have. People who are complaining about the higher voltage measured at the transformer clearly have no idea how this works. They just know enough to know how a DMM (voltmeter) works and that’s it. Additionally, most commercial circuits in medium to high end electronics have a tolerance for what the input voltage can be as well. Usually somewhere in the realm of +/- 10-15% of its highest input value. Moral of this story is, It’s perfectly safe to run this with a 24vac connected device. My credentials are I have a BS in manufacturing, and a PhD in Computer and electrical engineering.
...
show more
Reviewed in the United States on December 11, 2025 by D Wxby
Number of Items: 2
I purchased this for a ring doorbell. My mother didn’t want to set the wiring so we are using the existing wiring in the house already and needed something that would provide 24v output to the device. I tested the device first before plugging it in as my mother got her ring doorbell for free and I didn’t want to fry it. Red Lead on 0v and Black (power) on 24v. The readout was indeed AC, fluctuating from +24v to -24v with a max being +- 30v. The max the ring doorbell can take is 40v so that was great. I checked the connection of the wire for shorts and breaks (resistance) and everything was good. Set it up and it’s working fine. It’s perfect for my needs, though it is a bit bulky causing me to rearrange my plug but it is working and the ring doorbell is recognizing its connected to hardwire. My mother is happy and I got to use my Applied Integrated Technology degree. Win win.
...
show more
Reviewed in the United States on August 20, 2023 by Katrina L Sparks Katrina L Sparks
Number of Items: 1
So far, so good! Nice and clean and easy to use.
Reviewed in the United States on October 4, 2025 by Amazon Customer
Number of Items: 1
When I moved in, I upgraded my original (working) doorbell to a Ring camera doorbell. Within 1 year, the Ring stopped working. I suspect the old hardwire doorbell transformer got burned out from a higher voltage draw. Replacing the hardwired transformer would require cutting house power and opening the fuse panel. Instead, I simply bought this 24v transformer, added the doorbell leads to the transformer screws, and plugged it into a nearby socket. The ring doorbell has been working fine ever since.
...
show more
Reviewed in the United States on November 12, 2023 by infrequent buyer
Number of Items: 1
I purchased the Hotop 24VAC 40VA plug in transformer to replace the 25.5VAC 25VA plug in power supply that came with my Rainbird ESP-Me irrigation controller. The original power supplies are notorious for breaking, and used ones in good condition go for $70 on EBay. The Hotop plug in transformer is a little over-rated for what the Rainbird system needed, but the Hotop was one of the very few 3 prong grounded 120VAC inputs with a 3 wire 24VAC grounded output that I was able to find to match the original Rainbird power supply. I used the 3 wire cord from the original supply and connected it to the 24VAC screw terminals on the back of the transformer case. The measured voltage output from the Hotop read 27VAC with 124VAC input from my house outlet. The original power supply (25.5VAC output) supplied 29VAC, so I'm not worried as the 27VAC is within the range of the 24VAC control valves in my system. Excellent product for an excellent price.
...
show more
Reviewed in the United States on August 13, 2024 by Michael W. Robinson
Number of Items: 2
Needed a 24VAC transformer to power my new zone board for my AC unit. This transformers provides power to the zone board and full time power for two thermostats. It is great that it has a built in auto resetting fuse and plenty of power for multiple things at the same time. It does output slightly higher than 24V at just around 27V so make sure what you are using it for can operate at slightly higher voltages. In my case this is driving two zone damper motors, two thermostats and providing operational power to the zone board. Have had it in use now for a little over a month without any issues. I purchased the two pack to have a spare on hand. It is operating in my attic so will be susceptible to the heat of the summer and the zero degree weather of the winter. It does run warm to the touch when in use so be aware if you are using it openly in a living space. So only time will tell how it holds up to all the temperature swings and rigors of 24/7 usage.
...
show more
Reviewed in the United States on October 11, 2023 by Harvey W.
Number of Items: 1
Had it for a year to power smart thermostat. Works as it should.
Reviewed in the United States on November 20, 2025 by Dough
Number of Items: 1
This is not a bright white adapter as shown in photos. Disappointed it came in tan color when it arrived.
Reviewed in the United States on February 18, 2026 by A. Farfan A. Farfan