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Everything posted by bmachine

  1. Thanks oldgranpa and audioguru. Guru, Apologies for the 100k/1k mix up. When you fill out the "Reply" screen, you can't see the previous replies and I could not see the schematic so I erroneously thought it was 100k. I will follow your 1k directions of course. The reason I wanted to use two transistors is that the fog machine has actual 120V going through that relay while the lights just need a very low voltage short. I fear that if I hook up both my to output jacks in parallel to the one transistor, the 120v might fry the inners of the light controller. Bo
  2. Thanks very much audioguru. I am using a NTE R46-5D3-6 relay. Nominal voltage is 6VDC, coil resistance 100 ohms Nom power 360 mW Max contact current 5A Does that help? Bo
  3. Thank you audioguru and oldgranpa. Very good info. Your assumptions are correct oldgranpa in that I am reasonably new at this. So I very much appreciate your schematic. I am assuming that the "thing" on the right is the relay (right above the OR). So all I need is to add that transistor in between. As far as said transistor, is NPN its full description? In other words, if I go to Radio Shacsk, will the clueless helper be able to give me exactly what I need when I say NPN or is there a more specific part number to ask for? Thank you very much again. Bmachine
  4. I built a monstable 555 timer based on John Adams' shematic which stays on for 20 seconds. The output of that one feeds power to an astable version of the 555 circuit which blinks every two seconds. I have LEDs at each stage and everything works perfect. But when I add a relay in parallel with the LED (sending the ground and pin 3 to the coil of the relay) the relay just stays seems to try and close but does not (I hear a slight buzzing) and the LED does not blink anymore. When I hook up the 9v battery directly to the relay, it closes easily so the problem is not there. I thought it might be because there was not enough juice getting to it so I used a 9v dc wall wart but the results are the same. Any idea of what I might be doing wrong? Thanks very much. Bmachine
  5. Thank you very much for the answer and the schematic Audioguru. At first the file wouldn't open so I found a link for it here (hope it's OK to post links): http://members.shaw.ca/novotill/FireLightFlicker/index.htm I will give that a try. Bmachine.
  6. Wow! Excellent information, all. Thank you very much. I guess I'll go ahead and give this a shot. BTW, Is there a simple way to simulate a load for testing purpose? Bo.
  7. Hello, dumb question here. I need to use one of those little wall mounted ac/dc converter for a little 555 based project I am doing. I found an old one that is labeled to have a 9V DC output. But I put my voltmeter to it, it reads 14volts. I then tried a couple that were rated at 24v output and they read more like 28 or 29v. Is this normal? Is it because they need to be measured under some kind of load or something? Is my transformer really going to give 9V to my project or is it going to fry everything by delivering 14 volts? Thank you very much. Bmachine.
  8. Hello. Newbie here. I read with interest the article by John Adams about using a 555 as a timer I am trying to build a controller that would activate a relay in a "non regular" way. In other words, when I use the astable example John gives, depending on the values used, the circuit will give me "on for 1 sec, off for 2 secs, on for 1 sec, off for 2secs, etc...". This pattern repeats until power is turned off. What I would like is to get an irregular pattern such as "on for 1 sec, off for 2.7 sces, on for 0.8 sec, off for 1.4 secs, etc..." I am not too picky about the actual intervals, as long as it appears more random. I was thinking that I could run two 555s with one set for one timing (1 sec on and 2secs off for example) and then second one set for a different timing (1.6 sec On and 1.3 off for example. I would then take these two outputs and combine them to get a more irregular pattern to trigger my relay. My question is How do I combine these two outputs without getting overloads or feedbacks or whatever dangerous thing might happen if I simply connect them together before going to the relay. Or maybe there is a better way to achieve this... Any help would be greatly appreciated. Thank you Bmachine.
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