From a simple switch to a relay clock
Channel: HomoFaciens
Date: 2013-09-06

Table of content:
00:05 Introduction
00:46 Switch
01:20 Switching high power
02:27 Different types of switches
05:17 Contact bounce
06:36 Arcs
07:56 Reed contact / reed relay
08:59 DC relay (working principle)
10:41 DC relay at AC voltage
11:04 Sharing ring (working principle)
12:05 AC relay
12:44 Relays at AC/DC voltage
14:05 Pull-in and hold current / voltage
15:32 Switch time
16:21 Voltage peak while deenergizing a relay
16:50 Power dissipation of the control circuit
17:13 Soleonid switch
17:43 Impulse relay
18:05 Bistable relay (working principle)
18:54 Bistable relay (real device)
19:28 Unknown relay
22:49 Too high coil voltage
23:21 Simple relay circuits
24:21 Switching high power
24:54 Cascading relays
26:25 Some more simple circuits with relays
27:03 RS flip-flop (working principle)
28:52 RS flip-flop (real circuit)
29:57 T flip-flop (working principle)
33:34 T flip-flop (real circuit)
35:21 Asynchronous down counter
36:01 Astable multivibrator
36:39 Relay clock

The chapter about relays at the project page:
http://www.homofaciens.de/technics-base-circuits-relay_en_navion.htm