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Low voltage connection basics
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[edit] What is AC-voltage
AC-voltage is voltage where there is not a Plus and Minus terminal on the supply.
AC-voltage symbol 
Other Names for "AC-voltage"
- Directed power or voltage
- Sine wave power or voltage
- Inverter type of power or voltage
[edit] AC-voltage safety
AC electricity with a voltage less than 50 V (RMS) is called Extra Low Voltage. This voltage is unlikely to give a human being a dangerous electric shock.
[edit] What is low voltage
Other Names for "low voltage"
- Shock free power or voltage
[edit] What is DC-voltage
DC-voltage haves a Plus and Min.
DC-voltage symbol 
Other Names for "DC-voltage"
- DC power or voltage
- Battery type of power or voltage
- Plus-min power or voltage
[edit] Electric DC polarity PLUS and MIN
For most kind of devices it is important to have the right voltage and polarity. Wrong voltage or polarity can destroy a device
How to Mark the plus of to find the plus pole
- red is always plus.
- painted line on the plus wire, no line on the min.
- Plus wire is square, round wire is min
- sharp edge is plus, round wire is min
- knot is plus, no knot is min
- mark on the plus wire and so on, the plus wire is special or not normal than a normal wire.
- and so on, the plus wire is special or not normal than a normal wire.
These must be in good working order to save your electric material:
- The voltage
- The amperage
- The PLUS and MIN position
- The type of power AC or DC
- The type of low voltage coax connector
- protect your plug and connector against mechanical puling force
- take your time to check these 6 items
| sign on power output | or this sign | sign on power consumption | or this sign | harmful for output ? | harmful for power consumer ? |
|---|---|---|---|---|---|
 |  | | | no | no |
 |  | | | no | no |
| | | | no | YES ! |
| | | | no | YES ! |
| DC | | AC | no | YES ! |
| AC | | DC | no | YES ! |
[edit] electric current ampere
| amp. on
power output | or this amp. | amp. on
power consumer | or this amp. | harmful
for output ? | harmful for
power consumer ? |
|---|---|---|---|---|---|
| 500 mA | =0.5 A | 500 mA | =0.5 A | no | no |
| 400 mA | =0.4 A | 500 mA | =0.5 A | YES ! | no |
| 500 mA | =0.5 A | 400 mA | =0.4 A | no | no |
[edit] electric voltage
| volt output | volt consumer | harmful for
output ? | harmful for
power consumer ? |
|---|---|---|---|
| 12 V | 12 V | no | no |
| 9 V | 12 V | no | does not work well |
| 3 V | 12 V | no | does not work |
| 12 V | 9 V | no | YES ! |
[edit] adapter with different connectors
Protect your power supply
On the left power supply output in the right power receiving device
.
Plus and min
Adapter connectors
| OUTSIDE
(mm) | INSIDE
(mm) | Shortcut | Plug Type
(code) | mark |
|---|---|---|---|---|
| 6.5 | 1.0 | no | AA | = |
| 6.5 | 1.75 | no | AB | = |
| 2.5 | 2.5 | YES! | A (*) | = |
| 3.5 | 3.5 | YES! | B (*) | = |
| 3.0 | 1.0 | no | C | = |
| 5.0 | 2.1 | no | D | = |
| 5.5 | 2.1 | no | E | = |
| 5.0 | 2.5 | no | F | = |
| 5.5 | 2.5 | no | G | = |
| 3.5 | 1.35 | no | H | = |
| 4.0 | 1.7 | no | I | = |
| 4.75 | 1.75 | no | J | = |
| 5.0 | 1.5 | no | M | = |
| 5.5 | 1.5 | no | N | = |
| 5.5 | 5.8 | no | P | = |
| 6.3 | 3.0 | no | Q | = |
| 7.0 | 1.0 | no | R | = |
| 2.35 | 0.75 | no | S | = |
(*) Mono jack
[edit] What is electrical-short ?
Electrical short is when the plus and min are in contact with each other
This is harmful for the adapter or battery.
[edit] electrical-short with (dis)connecting device
Some smaller connectors shortcut the power supply if you (dis)connect .
(dis)Connect the connector to the device if there is NO power on the plug.
Right
[edit] Car cigarette lighter plug
A Car cigarette lighter plug must have the plus in the middle and the min on the outside.
Some female Car socket in some truck have 24 volt.
[edit] See also
external links
 | Information on Coaxial DC Power Connectors can be found at Wikipedia. |
