So there is this nightlight (a little flower that you plug in directly into a mains socket and switching it on gives you some light to light up your bedroom at night) which I dismantled and tried to know how its wired up. This is what I got:
simulate this circuit – Schematic created using CircuitLab
The mains is 230V AC @ 50 Hz and the capacitor C1 is of the shown type:
except its marking is
224K 200V
which I presume is 22E4 pF (ie 220 nF), 200V maximum voltage rating and K = 10% tolerance.
My questions are :
- Is the R1-C1 combination acting as a filter here? Is this common in this kind of rectifier circuit?
- I plan to make the same circuit, can the diodes be replaced by others from the 1N400X series?
- The markings on C1 shows it's a 220nF cap, but measuring capacitance across the cap gave a reading of 580nF. Is this the result of the other parts of the circuit?
- I plan to make the same circuit, is it a safe bet to use a 2.20 uF capacitor as C1 ?
EDIT: I had inadvertently swapped the values for R1 and R2. Now the circuit appears to be correct. I made the following measurements across the components during operation:
- \$\approx\$ 14mA through each LED
- \$\approx\$ 2.95 V drop across each LED
- \$\approx\$ across each diode
- \$\approx\$ 1.37 Vdc across R2
- \$\approx\$ 217.5 Vac drop across R1