# Variable Pulse Frequency Generator (70)

**Circuit** (70) of Figure (3-5) is a **multi pulse-frequency generator** which produces several clock pulses (*simultaneously*) **having different pulse-frequency** but <span style="text-decoration: underline;">maintaining a 50% duty cycle pulse</span> (39) configuration, as illustrated in Figure (3-16).

<table border="1" id="bkmrk-figure-%283-5%29-figure-" style="border-collapse: collapse; width: 100%;"><tbody><tr><td style="width: 49.9383%;">Figure (3-5)

[![image-1703195613050.png](https://stanslegacy.com/uploads/images/gallery/2023-12/scaled-1680-/d5x6lw5jRAJT48i1-image-1703195613050.png)](https://stanslegacy.com/uploads/images/gallery/2023-12/d5x6lw5jRAJT48i1-image-1703195613050.png)

</td><td style="width: 49.9383%;">Figure (3-16)

[![image-1703198042496.png](https://stanslegacy.com/uploads/images/gallery/2023-12/scaled-1680-/9eo48JVGQNzatQ86-image-1703198042496.png)](https://stanslegacy.com/uploads/images/gallery/2023-12/9eo48JVGQNzatQ86-image-1703198042496.png)

</td></tr></tbody></table>

**Pulse on-time** (37) and **pulse off-time** (38) are <span style="text-decoration: underline;">equally displaced</span> to form **duty pulse** (39) which is duplicated in succession to produce **pulse train** (41) of Figure (3-16).

Increasing the number of duty pulses (39a xxx 39n) up to **pulse frequency range** of 10Khz or above now forms **clock signal** (21) of Figure (3-5) which, in turns, performs the scanning function of **Acceleration Control Circuit** (30) of Figure (3-5).

**Circuit** (70) also produces another independent and separate **clock signal** (41a xxx 41n) which is electrically transmitted to and become incoming **clock signal** (42) for **Gated Pulse Frequency Generator Circuit** (80) of Figure (3-5).

In both cases, pulse frequency range of each **clock signal** (21) and (42) can be altered or change (controlled independent of each other) to obtain peak performance of **Fuel Cell System** (100) of Figure (3-5).

[![image-1703195613050.png](https://stanslegacy.com/uploads/images/gallery/2023-12/scaled-1680-/d5x6lw5jRAJT48i1-image-1703195613050.png)](https://stanslegacy.com/uploads/images/gallery/2023-12/d5x6lw5jRAJT48i1-image-1703195613050.png)