bitem2k
New Member
Hi , does anyone have any experience of 555 failure?
I made simple strobe light pcb, which works fine. Then suddenly after if not being switched on for a day or so, it refuses to flash, and just lights the leds constantly.
Does anyone have any ideas what might cause this?
It has happened several times with several different chips.
My power supply is 9v. Im driving 4 superbright leds at 3.8v each @20mA.
I have wired them into two series sets consisting of 2 leds and a resistor for each set, these two sets of leds are then wired up to the collector of a transistor.
I have wired pin 3 of the 555 to a resistor and the resistor to the base of a transistor which switches 40mA (two lots of series leds). I have used the transistor in case of me needing to switch heavier loads in the future.
Thanks very much.
I made simple strobe light pcb, which works fine. Then suddenly after if not being switched on for a day or so, it refuses to flash, and just lights the leds constantly.
Does anyone have any ideas what might cause this?
It has happened several times with several different chips.
My power supply is 9v. Im driving 4 superbright leds at 3.8v each @20mA.
I have wired them into two series sets consisting of 2 leds and a resistor for each set, these two sets of leds are then wired up to the collector of a transistor.
I have wired pin 3 of the 555 to a resistor and the resistor to the base of a transistor which switches 40mA (two lots of series leds). I have used the transistor in case of me needing to switch heavier loads in the future.
Thanks very much.