Multivibrators (introductory)
Analog electronics · Physics
DC circuit
Interactive 3DElectrons drift around the loop — raise the voltage and watch the current obey Ohm's law.
Controls
Drag the sliders or type a value — the simulation updates live.
V
1V12V
Study notes
Worked example - 555 astable blinker. Choose R1 = 1 kohm, R2 = 10 kohm, C = 10 uF. Step 1: f = 1.44/((R1 + 2R2)C) = 1.44/((1000 + 20000) x 10 x 10^-6) = 1.44/0.21 = 6.86 Hz - about 7 blinks per second. Step 2: duty cycle = (R1 + R2)/(R1 + 2R2) = 11k/21k = 52.4% high. Step 3: for a 1 Hz clock (one blink/sec), scale C to ~68 uF: f = 1.44/(21000 x 68 x 10^-6) = 1.008 Hz. Note the 555's frequency drifts ~with temperature and supply - fine for a blinker, not for a watch.