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Low-power CMOS timer

TLC555 Working Principle

Learn how TLC555 works with an illustrated explanation and practical readings.

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TLC555 at a glance

Follow the labeled connections and functional stages

TLC555 working principle: illustrated functional stages, basic circuit and connections
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How it works

3 stages · Explore one step at a time

Step 1 / 3

Charge

With DISCH open, the capacitor charges through RA plus RB until THRES crosses the upper threshold.

Step 2 / 3

Discharge

The latch changes state, OUT goes LOW, and DISCH drains the capacitor through RB.

Step 3 / 3

Repeat

When TRIG crosses the lower threshold, the latch sets and the next HIGH interval begins.

Two timing networks. Two waveforms.

Adjust each channel and compare its ideal steady-state timing.

RC timing calculator

CMOS timer OUT · pin 3

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Supply: 5 V. Each graph uses its own time scale. Nominal astable calculator; not a device simulation. RESET HIGH, CONT unmodulated. Tolerances, startup, leakage and output loading are not modeled.

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