Blog

555 Frequency Synthesizer

jc2048 — Fri, 08 Jul 2022 15:33:00 GMT

In the previous blog I took a simple 555 oscillator that had been adapted for voltage control and used it as a component part of a phase-locked loop (PLL). In this final blog, of what has turned out to be a series, I'm attempting to use...(read more)

555 Phase-Locked Loop (PLL)

jc2048 — Wed, 29 Jun 2022 10:16:00 GMT

In the previous blog I took a simple 555 oscillator and adapted it so that it was voltage controlled (a VCO). In this blog I'm going to carry on and use that VCO as a component part of a phase-locked loop (PLL). This is the overall circuit now. ...(read more)

555 Voltage Controlled Oscillator

jc2048 — Mon, 13 Jun 2022 08:48:00 GMT

In the last blog, I used a 555 timer to make a simple oscillator. It used an additional transistor, as a current source for the capacitor charging, in place of the resistor that would usually be used. Although the blog focused on the linear nature of...(read more)

555 Sawtooth Oscillator

jc2048 — Mon, 06 Jun 2022 22:10:00 GMT

The ST datasheet for the 555 has this circuit for generating a linear ramp. The linearity comes from the use of a transistor to give a constant current source for the capacitor charging.As shown, it's a monostable (it's designed to generate the ramp ...(read more)

555s Used as Monostables

jc2048 — Tue, 10 May 2022 11:47:00 GMT

I've never used a 555 timer as a monostable, so I thought I'd give it a go. This should be easy, shouldn't it. Here's the circuit as it's given on an old ST datasheet. As they describe it, a falling edge at the trigger input sets the output and...(read more)