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Silly Job Title: Digital Dancer. I am the Digital Dancer!

In this video we have a look inside Encyclopedia of Electronic Circuits Volume 2.

Circuits of particular interest were:

Some notes concerning things which came up:

SCS = Silicon-Controlled Switch: an SCS (Silicon-Controlled Switch) is a four-layer thyristor device — basically an SCR with an extra gate — that gives you extra control (including a way to force it off). It’s a member of the thyristor family used for controlled switching in low-power applications.

Ga = Gallium.

As = Arsenic.

P = Phosphorus.

Compander = compressor + expander. It’s a system (or device) that compresses the dynamic range of a signal before transmission or storage and then expands it back to (approximately) the original dynamic range at the receiver/playback end.

The NE570 / NE571 (and SA571) are dual compandor ICs: each chip contains two identical compressor/expander “kits” (full-wave rectifier → temperature-compensated variable-gain cell → op-amp + trim) used for dynamic range control and noise-reduction in audio/communications systems. They’re widely used as companders, VCAs, limiters/noise-gates and as the compressor/expander around BBD delay lines to reduce hiss.

β (beta) — also written h_FE or hfe on datasheets — is the transistor’s current gain. For a bipolar junction transistor (BJT) it’s the ratio of collector current to base current: β = I_C / I_B.

Q (quality) factor: measures how selective or sharp a resonant system is. High Q → narrow bandwidth, slow damping (lots of ringing). Low Q → wide bandwidth, heavy damping (quickly dies out).

I asked ChatGPT to please explain damping and ringing.

The 5558 IC is a dual op-amp in the 1458/1558 family (often labelled LM1558 / MC1558 / 5558 depending on maker). These are general-purpose, internally-compensated dual operational amplifiers (audio, filters, integrators, buffers).

My programmable load is the ZKETECH EBD-A20H Electronic Load.

SCA = Subsidiary Communications Authorization / subcarrier (used for background music/data in FM radio broadcasting).

We encountered Chebyshev filters which are analog or digital filters that have a steeper roll-off than Butterworth filters, and have either passband ripple (type I) or stopband ripple (type II).

UJT = Unijunction Transistor, a three-terminal semiconductor device (Emitter E, Base1 B1, Base2 B2) with a single PN junction and an internal resistive path between B2 and B1. It’s widely used as a simple relaxation-oscillator/timing/trigger device because it shows a controlled negative-resistance region when the emitter is driven above a threshold.

PUT = Programmable Unijunction Transistor; a PUT is a three-terminal semiconductor device (Anode, Cathode, Gate) that behaves like a unijunction transistor but whose trigger (peak) point is set externally by resistors — i.e. it’s programmable. It’s essentially a four-layer PNPN device (closely related to SCRs in internal construction) with the gate used to set the firing threshold.

My anti-static monitor is an Auto-alarm Anti Static ESD Wrist Strap Tester Output Anti-static Online Monitor For Anti-static Electronic ESD Meter.

A squib is a small explosive which can be used as a detonator.

A “TR circuit” can mean variously:

• a T/R (transmit–receive) switch used in RF systems
• a transformer-rectifier (TR or TRU) — a transformer plus rectifier used for AC→DC power
• Tr often used as an abbreviation for rise time (tᵣ) when discussing pulse/transient performance

SSB = Single-SideBand — a form of amplitude modulation where the carrier and one of the sidebands are removed so only one sideband (upper or lower) is transmitted.

The 2N4871 is a classic silicon PN unijunction transistor (UJT) used for timing/oscillator and trigger circuits.

RTD = Resistance Temperature Detector, a temperature sensor that measures temperature by sensing the electrical resistance of a metal element, which changes predictably with temperature. RTD stands for Resistance Temperature Detector.

A Theremin is a type of musical instrument.

The 4069 is a hex inverter.

The 4046 is a Phase-Locked-Loop.

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