Electronics can be found all around the world, these are: TV's, Radios, Walkie Talkies, Flashlights etc. You can get electronic components from them, these are: Electronic scrap (most important), radio receivers, radio transmitters, electric wire, motion sensors, amplifiers.
You use these components to make useful electronic timers, triggers etc.
To use that, you first need to make a trap (engineer profession required for most of them, others can be learned), these are smoke bomb and noise maker (magazine recipes can be found) pipe bomb, aerosol bomb, flame trap (engineer profession required)
You will need a screwdriver for all electronic crafting recipes

Electronic scrap is used for everything, it is a basic component, it can be crafted by dismantling everything
Electric wire is used in crafting makeshift radios (not very useful right now, but might be in multiplayer or NPC update)
Radio transmitter is used for radios
Radio receiver is used for radios, but most importantly for trigger activation mechanism for your traps
Motion sensor is used for making traps that activate by motion, can be crafted my dismantling home alarm or finding inside electrician houses.
TV remote is very important, it is very rare and is used for making a remote controller to activate triggers. It can be rarely found in bedrooms and counters in electrical stores.
Crafted trigger is used for traps to activate by remote controller
Amplifiers are used to make noise makers.

Controllers are remotes used to activate triggers attached to traps
There are 3 versions, V1, V2 and V3
Recipe is required to be known to make these, magazine can be found but electrician knows them by default
V1 is the least range (7 tiles) and level 2 of electrical skill is required
V2 is more range (11 tiles) and level 4 of electrical skill is required
V3 is the most range (15 tiles and level 6 of electrical skill is required
To make one, you need 2x Electronic scrap, 2 units of glue (full glue is 5 units), TV remote and a screwdriver
Using it is pretty simple, all you have to do is link your trigger to your remote so they use a same code, now when you deploy a trap with a trigger you can activate it, multiple traps can be linked to the same remote and activated, note that remote does not have a condition and can be used infinitely. Finding a controller is much more efficient than making one, and can be found in electrician houses, V3 is pretty common there and its much more easier finding it than grinding until level 6 and finding a TV remote.

These are things you need to make traps
Noise maker 7 electronic scrap and 1 amplifier
Smoke bomb 2 Newspaper 1 Cold pack
Flame trap Half a gasoline canister, 1 ripped sheets or dirty rag, 1 empty (regular water) bottle
Pipe bomb 1 Metal pipe, Small usage of twine, Saw or Garden Saw, 2 Gunpowder and 3x Electronic scrap
Aerosol bomb 1 Hairspray 1 Box of sparkles 1 Aluminum

Noise makers are good for moving hordes or spreading them out, using it will make all the zombies move around and spread out or move to a location the noise maker was thrown, the noise maker has small range so it is good to use it to disorganize the horde to easily bait them out and kill them one by one
Pipe bombs are used primarily for dealing damage and burning zombies, they can also destroy walls easily.
Aerosol bombs deal smaller damage but do more fire that burns zombies and should be used exactly for that
Flame traps deal no explosive damage, but have high area of effect, the flame trap makes up to 10 flame puddles around its area of effect and zombies quickly catch fire
Smoke traps when thrown at zombies confuses them and makes them stop and wait for the smoke to clear out, can be useful when being chased by a horde

Aluminum - Dismantle any electronic like TV, Radio or Walkie talkie
Hairspray - Toilets
Box of sparkles - Kitchen counters (rare)
Metal pipes - Sheds, warehouses, hardware stores etc.
Twine - Sheds, warehouses, hardware stores etc.
Saw - Sheds, warehouses, hardwares stores etc.
Amplifier - Dismantle any radio, walkie talkie or TV
Cold pack - Freezers

Now that you know about components of both traps and electronics it is time to combine them.
Timers are made by combining alarm clocks or timers, 1x electronic scrap and 1 unit of glue, it requires 1 electrical skill
Triggers are made by combining 1 radio receiver, 2x electronic scrap, 2 unit of glue, to activate you need a remote controller
Motion sensors are found or dismantled through house alarms (rare item)
To attach any trap you will need electrical skill level 2, 1 unit of duct tape, 2x electronic scrap and of course a screwdriver.

Noise makers are good to be thrown at hordes to disorganize them and spread them out. This will make it so that you can bait zombies out easier and kill them off one by one, it can also be used to move a horde away, but this tactic can be dangerous since zombies spread out and there is a chance that some of them will see you.
Timers make it so that you add a countdown to an explosion, this can be useful when expecting larger hordes at exact time, which is using sirens of police cars, ambulance vehicles etc. to call bigger hordes, to do this the siren vehicle needs to be close to huge numbers of zombies, you activate the traps to 200-300 seconds and activate the sirens, you need to hide close so the trap stays in your loaded chunks, now you wait for the zombies to pile up, the traps will eventually explode dealing damage and spreading fire over the zombies, this can be really dangerous since the fire might spread over nearby buildings.
Motion sensors are mostly useful for hurting other players, but can be used against zombies aswell, although there aren't many useful tactics for zombies.
Remote triggers are great because you choose when to activate the trap, you can put multiple traps and bait zombies to them, then activate them, although the range is pretty low, the traps can still prove useful in some situations.

Electrician and Engineer start with electronic skill which also adds bonus to further leveling.
Although when going with traps you should pick engineer as your profession because if you dont, you will only be able to use smoke bombs and noise makers.
To level up it is advised to first read the book needed for the levels you are going to build up.
Dismantle every electronic you find (except TV remote, DO NOT DISMANTLE THE TV REMOTE), video game, TV, radio, Walkie talkie, CD player, cordless phone, etc.
The skill will go up and you will eventually level up, every time you secure the house and loot it, pick up the tv and dismantle it, i usually drop the electric wire since its only used for radios, take all the electronic scrap and receivers/transmitters, aluminum is needed but in smaller quantities since its used for aerosol bombs which need 1 per bomb and boxes of sparklers are extremely rare and aluminum is not.

Radios aren't that useful, there is a makeshift radio, makeshift ham radio and makeshift walkie talkie.
The radios will probably be more useful in multiplayer or NPC update (if we ever get it)
For now you may craft these radios to listen to broadcasts in the first 14 days, after it there is no more broadcasts except the weather update.
Making a walkie talkie requires you to get your hands on a radio transmitter and radio receiver which is obtained by dismantling a walkie talkie so that makes no sense, same goes by ham radio and regular radio, there is no point in making them, but the recipe can be obtained by reading the guerila magazines VOL 1-3