555 timer and beyond

Question

I've been studying the 555 Timer and I need to learn more then LED lighting: A stable, mono Stable and bi stable mode with IC's 
 My configuration: push button --> to 555 Timer--> Mini Solenoid and press the solenoid triggers. (what resistor if needed for solenoid)

beacon_dave · Accepted Answer

Perhaps join Derek over at 'DC to Daylight' where he shows you how to drive a relay coil, do the math, and demonstrates why you may want to use a diode across the coil: 
 /challenges-projects/element14-presents/dc-to-daylight/w/documents/27565/dc-to-daylight-09-how-electromechanical-relays-work?ICID=dctodaylight-episode-list 
 /challenges-projects/element14-presents/dc-to-daylight/w/documents/27596/dc-to-daylight-10-using-relays-to-make-a-vegas-style-sign?ICID=dctodaylight-episode-list 
 As a bonus, a 555 timer makes a guest appearance in the second one.

KennyMillar · Answer

Hi Limster10 
 The 555 Is nice - it's been a mainstay of electronics for decades! I'm glad you are studying it. 
 Using it to drive a solenoid is neat idea too. It's hard to give you any specific answer without seeing a schematic of what you're doing. (Even a hand draw sketch is fine!) 
 Solenoids are inuductive devices, and if you wire it directly to a 555, you stand the chance of damaging the timer chip. Look at the datasheet for your specific 555 and see what the maximum current source is on the output, and pay specific attention the maximum ratings for the device. 
 If it were me, I would connect the 555 to a Transistor, or MOSFET to drive the solenoid, with an appropriate diode across the solenoid windings to snub any back-emf.

555 timer and beyond

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