Well this is rhetorical question. And then, on a very important sector, pose great 'savetskuyu' button 'Start', 'perfect' work of which we are sure will pay a whole paragraph! Original, well, technology selection components! 2. Come on, pay attention, the circuit has no solutions to the food! (Save on food! Rough and common mistake beginners on the 1 st year at college.) To power supply decoupling, we shall return, and now see how this scheme is implemented. Input voltage is damped by resistor and capacitor (the important part), which is then supplied to the domestic assembly and stabilizes KTS407 stabilitron coupled with capacitor! This circuit design is highly dependent on network parameters and the parameters of ingredients and the quench tank capacitor (shamanism) There is visible 'concern' about the economy of the product! – And this after using expensive high-CMD Capacitors + expensive power SMD resistor! And the setting! In the shaman drum beat when setting up the scheme, not otherwise. (Similarly see: muscular dystrophy). Let's see what the load – are not that small: 3 powerful greedy relay and a scattering of transistors that also eat want. As a result, schematics for the stability of the block 'justify' themselves completely customize every piece had to be individually, in one word 'industrial' automatics. Another feature of the scheme is able to choice of food from 3 sources, 220V, 24V, 12V, a 'wise' decision and save! Adjustment is carried out, without further ado – the jumpers! Looks ispulsny power supply (transformer at the worst) – Engineers at the NPF SWEET – redundant element Indeed, why should I care if there are resistors, capacitors, zener yes. .