556 timer help...
Posted: Sat Dec 03, 2011 9:58 pm
i been looking for a circuit. i caught a glimpse of it and have been trying to duplicate it. but have had little luck. i'll try to explain it, and see if someone might have something similar to it.
its supposed to be a muscle massager of sorts. i am wanting to use it to play with neon flicker bulbs,
different frequencies make them flicker more and make them look more realistically.
the duration pulses (on/off) can be from 0% to 100%
and the frequency i think was from 0Hz to maybe 500Hz.
and both had a common output thru the audio transformer..
something along them lines.. does not have to be exact, once its working i can expiriment with caps etc to get it to do what i want.
anyway it uses a simple 556 timer, a small audio transformer.
2 control pots. 1 controls on/off time ( duration ) the 2nd one controls frequency.
i did see that the output pin-9 goes to a cap and then to the primary of the transformer.
pin 10 and 5 are connected together and go to a 1k resister and then to the base of a transistor.
the transistor drives a led as a visual indicator.
1st pot connects to pins 1 and 2
2nd pot connects to 13 and 14
pins 2 & 6 are jumped together
pins 8 & 12 are jumped together
also seen...
resistor on pins 1 & 14 = 43K
resistor on pins 12 & 13 = 33K
a non polar cap on pins 7 & 8
that's about all i was able to gather.
i thought i could make it work. but when i did the output on pins 5 & 6 would not completely go on/off, thus the transistor would stay full on or dim. but never off..
it was a 2N2222 PNP collector went to ground. emitter went to the led.
i probably could with 2 single 555's but i do not know how to make the frequency and duration work together.
anyone have any ideas on this ?
tried to look for something similar in the radio shack 555 cookbook. but nothing close..
its supposed to be a muscle massager of sorts. i am wanting to use it to play with neon flicker bulbs,
different frequencies make them flicker more and make them look more realistically.
the duration pulses (on/off) can be from 0% to 100%
and the frequency i think was from 0Hz to maybe 500Hz.
and both had a common output thru the audio transformer..
something along them lines.. does not have to be exact, once its working i can expiriment with caps etc to get it to do what i want.
anyway it uses a simple 556 timer, a small audio transformer.
2 control pots. 1 controls on/off time ( duration ) the 2nd one controls frequency.
i did see that the output pin-9 goes to a cap and then to the primary of the transformer.
pin 10 and 5 are connected together and go to a 1k resister and then to the base of a transistor.
the transistor drives a led as a visual indicator.
1st pot connects to pins 1 and 2
2nd pot connects to 13 and 14
pins 2 & 6 are jumped together
pins 8 & 12 are jumped together
also seen...
resistor on pins 1 & 14 = 43K
resistor on pins 12 & 13 = 33K
a non polar cap on pins 7 & 8
that's about all i was able to gather.
i thought i could make it work. but when i did the output on pins 5 & 6 would not completely go on/off, thus the transistor would stay full on or dim. but never off..
it was a 2N2222 PNP collector went to ground. emitter went to the led.
i probably could with 2 single 555's but i do not know how to make the frequency and duration work together.
anyone have any ideas on this ?
tried to look for something similar in the radio shack 555 cookbook. but nothing close..