Cubicle_22
New Member
I've soldered together two identical circuits similar to the drawing attached.
**broken link removed**
I made a few modifications to the circuit to reset the 4017 counter and 555 counting on startup - these mods work fine.
I also have the output from the 4017 counter flipping a relay using a npn transistor.
Both circuits flash at the same rate - at room temperature.
Here's my problem...
If I add a little heat to one of the circuits - using a hair dryer - just enough to warm the circuit board - the leds start flashing SLOWER.
I'm using two 10 uF tantalum capacitors.
Using the heat from the soldering iron I found that polyester capacitors - when heated - sped up the circuit.
I REALLY need to figure out how to get both circuits running at the same rate under different temperatures - say 0F to 100F - for an automotive application.
Any ideas?
![Confused :confused: :confused:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Confused :confused: :confused:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Confused :confused: :confused:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
**broken link removed**
I made a few modifications to the circuit to reset the 4017 counter and 555 counting on startup - these mods work fine.
I also have the output from the 4017 counter flipping a relay using a npn transistor.
Both circuits flash at the same rate - at room temperature.
Here's my problem...
If I add a little heat to one of the circuits - using a hair dryer - just enough to warm the circuit board - the leds start flashing SLOWER.
I'm using two 10 uF tantalum capacitors.
Using the heat from the soldering iron I found that polyester capacitors - when heated - sped up the circuit.
I REALLY need to figure out how to get both circuits running at the same rate under different temperatures - say 0F to 100F - for an automotive application.
Any ideas?