I'm just starting to learn about electronics by working through Charles Platt's Make: Electronics book and I'm on experiment 14, which is a relaxation oscillator for an LED. I should note that in the schematic below, I wasn't able to figure out how to add a PUT (2n6027), so 'D4' is in fact a PUT.
When I increase R3, my intuition tells me that since I'm increasing the capacitor time constant, the capacitor should take longer to charge and thus I should see a longer time in between flashes. In practice, exactly the opposite happens. As I increase R3, the LED flashes more and more frequently. If I put in a 10K resistor for R3, the LED flashes so quickly that it appears to be staying on continuously (or the voltage across the anode of the PUT stays continuously above the gate voltage for some reason). Why does the frequency of the LED flashes increase, rather than decrease, when I increase R3?