http://groups.yahoo.com/group/Electronics_101/ Electronics Learning Group Wed, 19 Jun 2013 05:44:27 GMT Jong Kung http://groups.yahoo.com/group/Electronics_101/message/82530 http://groups.yahoo.com/group/Electronics_101/message/82530 Tony, Learning about switching power supply is a good thing. But if you are interesting in the final product (sky tracking camera mount) and not out to learn Wed, 19 Jun 2013 05:31:08 GMT Jong Kung http://groups.yahoo.com/group/Electronics_101/message/82529 http://groups.yahoo.com/group/Electronics_101/message/82529 Tony, As Steve noted, you have to be careful that your LOAD (the actual circuit outside of 555 config) is not too big. With this configuration, your 555 output Wed, 19 Jun 2013 04:23:51 GMT Tony http://groups.yahoo.com/group/Electronics_101/message/82528 http://groups.yahoo.com/group/Electronics_101/message/82528 Hi Steve: Many thanks. So something like a 470 ohm resistor from pin 3 back to pins 2 and 6 ? Wed, 19 Jun 2013 04:23:23 GMT John Popelish http://groups.yahoo.com/group/Electronics_101/message/82527 http://groups.yahoo.com/group/Electronics_101/message/82527 That is one of the control chips available, but there are little boards that have the whole thing assembled, for a very reasonable price. i.e. Wed, 19 Jun 2013 04:17:22 GMT James M. Geidl http://groups.yahoo.com/group/Electronics_101/message/82526 http://groups.yahoo.com/group/Electronics_101/message/82526 Take a look at the link I have attached, it is only a beginning. I have no idea about your specifications as to motor size, etc. but you said mini so the L293 Wed, 19 Jun 2013 04:11:10 GMT Tony http://groups.yahoo.com/group/Electronics_101/message/82525 http://groups.yahoo.com/group/Electronics_101/message/82525 Hi John: So, something like this on eBay: http://www.ebay.com/itm/2Pcs-LM2576T-ADJ-Voltage-Adjustable-Switching-Regulator-/370820860629 Thx. Tony. Wed, 19 Jun 2013 04:06:33 GMT Howard Hansen http://groups.yahoo.com/group/Electronics_101/message/82524 http://groups.yahoo.com/group/Electronics_101/message/82524 Another good source for 0.47 ohm and 0.75ohm resistors is Digikey. See the following page for through hole 0.47 and 0.75 ohm resistors. Wed, 19 Jun 2013 02:28:48 GMT Frank Mead http://groups.yahoo.com/group/Electronics_101/message/82523 http://groups.yahoo.com/group/Electronics_101/message/82523 Your best bet is Mouser electronics.... ... [Non-text portions of this message have been removed] Wed, 19 Jun 2013 02:18:34 GMT AlienRelics http://groups.yahoo.com/group/Electronics_101/message/82522 http://groups.yahoo.com/group/Electronics_101/message/82522 I think you mean that they are not on for equal lengths of time, IE, the duty cycle is not 50%. It is impossible for them to blink at different rates. The Wed, 19 Jun 2013 02:06:05 GMT AlienRelics http://groups.yahoo.com/group/Electronics_101/message/82521 http://groups.yahoo.com/group/Electronics_101/message/82521 How about the L298? It is usually used as a stepper driver, but one IC has two separate H-bridge drivers that can control two DC motors bidirectionally. Wed, 19 Jun 2013 02:01:15 GMT claiudiu_2005 http://groups.yahoo.com/group/Electronics_101/message/82520 http://groups.yahoo.com/group/Electronics_101/message/82520 Does any of you have an idea how could i make Mini Dual H-Bridge Circuit from scratch ? I need to control 2 dc motors. I need the schematic of it. Or what Wed, 19 Jun 2013 02:00:48 GMT Hamilton Elliott http://groups.yahoo.com/group/Electronics_101/message/82519 http://groups.yahoo.com/group/Electronics_101/message/82519 Hi, I too have found a couple of resistors with the silver band and was puzzled by them. I now need to replace some 0.47 ohm resistors but I have no idea where Wed, 19 Jun 2013 01:31:04 GMT John Popelish http://groups.yahoo.com/group/Electronics_101/message/82518 http://groups.yahoo.com/group/Electronics_101/message/82518 The regulator, in that circuit, will ignore battery voltage changes until they get within about 1.5 volts of the motor voltage. So, for most of the battery's Wed, 19 Jun 2013 01:20:10 GMT Tony http://groups.yahoo.com/group/Electronics_101/message/82517 http://groups.yahoo.com/group/Electronics_101/message/82517 This article has a regulated voltage circuit at the end of the article http://www.garyseronik.com/?q=node/52 However, if running this circuit off a 9v battery, Tue, 18 Jun 2013 22:25:47 GMT jongkung01@... http://groups.yahoo.com/group/Electronics_101/message/82516 http://groups.yahoo.com/group/Electronics_101/message/82516 Completely agreed. That's why we use digital IC / uC anyway - to simplify and even make them efficient. I was just making a point it is good to learn analog