Determining which capacitor for a latching pushbutton circuit with NANDs

Question

I am working on a latching push-on/hold-off circuit for a momentary button and I am stuck with determine which type of capacitors to use. The circuit is detailed below (originally from Mosaic Industries):

^{simulate this circuit – Schematic created using CircuitLab}

I am unsure whether or not this will work with electrolytic capacitors, and if it will which polarity should they be? I have considered ceramic capacitors, but I am unable to easily source 1uF ceramic capacitors. As the schematic does not indicate that they are polarised capacitors I suspect that ceramics are the only option, but if this is the case what value would be ideal given I can only find values less than 1uF.

For this circuit I am using a CD4011 NAND IC.

Any advice is greatly appreciated.

Answer 1

The big capacitor and resistor at the bottom of the circuit are used to produce a 5 second RC time constant so that to get the lamp to turn off one has to press and hold the switch for a long time (~ 3 seconds). The smaller RC components at the top of the circuit act so that a quick button press will turn the lamp on again.

You don't say what value ceramic capacitors you do have, but if you cut the capacitor values in half you will cut the time constants in half. If you want to restore the time constants simply double the resistor sizes.