# AC to DC Power conversion

#### mukund_bm

Joined Aug 24, 2014
9
I am new to Electronic, i would like to know AC to DC conversion without transformer is safer or with transformer?

Using the Converting AC to DC using Capacitor as below listed table
 Capacitor Code Capacitor value Voltage Current 104k 0.1 uF 4 v 8 mA 334k 0.33 uF 10 v 22 mA 474k 0.47 uF 12 v 25 mA 684k 0.68 uF 18 v 100 mA 105k 1 uF 24 v 40 mA 225k 2.2 uF 24 v 100 mA

#### andrewmm

Joined Feb 25, 2011
627
degrees of safe .

Used safely , both with and without a transformer is "safe", !!

You show an ambiguous table,
a circuit diagram of what your thinking would be needed to help us determine your question

#### DickCappels

Joined Aug 21, 2008
6,640
If you are new to electronics then a power supply without a transformer for isolation from the mains would pose a grave danger to you. Most likely you will only experience painful shocks occasionally but there is always a chance of a lethal shock or damage (such as burns and cuts from reactions to being shocked).

I try to use wall warts or other already made power supplies deisnged and certifieid to be safe as often as possible. The hard part is already done and is ready to use, leaving more time on the special parts of projects.

#### mukund_bm

Joined Aug 24, 2014
9
Dear Andrewmm, thank you for immediate response.

I have created Water pump using Solenoid valve, as part of the Circuit there will be 2 power inputs

1 is for Circuit
2 is for Solenoid Valve

To avoid 2 transformer, it would be better to use Capacitor based. Kindly advice.

#### dl324

Joined Mar 30, 2015
11,823
i would like to know AC to DC conversion without transformer is safer or with transformer?
Using the Converting AC to DC using Capacitor as below listed table
Your statements and table are meaningless without more context.

Where is the AC coming from? What is it's voltage? What DC voltage are you trying to generate? At what current?

#### Dodgydave

Joined Jun 22, 2012
9,631
Ok what DC voltage do you want and what current are you expecting to draw?.

#### mukund_bm

Joined Aug 24, 2014
9
Input AC 230V to DC 24V 2A for solenoid and DC 5V 1A for Microcontroller

#### DickCappels

Joined Aug 21, 2008
6,640
How big would the capacitor have to be in order to supply on the average 3 amps?

Does your microcontroller connect to anything outside of the solenoid circuits?

#### dl324

Joined Mar 30, 2015
11,823
Input AC 230V to DC 24V 2A for solenoid and DC 5V 1A for Microcontroller
It's safer to use a transformer.

You can buy a 24V power adapter for less than it would cost you to build one. From that, you can use a switching regulator to get 5V at 1A.

#### Alec_t

Joined Sep 17, 2013
11,728
Just dropping the voltage with a capacitor is unsafe and not practical for those currents. You must use a transformer, be it one designed for 50/60Hz or one inside a high-frequency switch-mode power supply. The transformer provides isolation from the mains for safety.

#### PhilTilson

Joined Nov 29, 2009
86
Whilst agreeing with the previous warnings, I would add that designing a water pump using a solenoid and proposing to use capacitive voltage level changing to run it sounds like a disaster waiting to happen!