.. was to amplitude-modulate the power output stage of an infrasonic microphone ( Ref. 2 )That gadget generated both the sub-10 Hz baseband signal and an audio tone whose pitch varied linearly with it, allowing one to hear at least a proxy for ...
LEDs need current to illuminate, and current usually flows through a power supply to an LED. A typical LED-driver circuit uses a transistor to provide current and a series resistor to decrease the voltage you apply to the LED. Unfortunately, the ...
.. the mismatch between test parts A and B. The resulting difference signal is boosted by preamp A1d in switchable gains of 1, 10, or 100, synchronously demodulated by U1a, then filtered to DC with a final calibrating gain of 16x by A1c. The key ...
.. I expect it to operate at the lower frequencies at least as well as Woodward’s circuits. Operation down to 1 Hz or 10 Hz is, in my opinion, mostly for bragging rights, and I am not concerned about that. I expect this VFC to be useful ...
We’ve seen lots of interesting conversations and Design Idea (DI) collaboration devising circuits for power switching using inexpensive (and cute!) momentary-contact SPST pushbuttons. A recent and interesting extension of this theme by ...
.. NPO/COG capacitors and the resistors of the values and tolerances shown in the schematic are available for well under $0.10 in 1000-piece quantities. The filter shown is a 3 rd -order one (evident from the presence of three capacitors). ...
.. instantaneous 60-Hz half-wave polarity. The type H11D1 300-V opto has a typical current transfer ratio of 80% which makes ~10 mA of PWM drive current necessary. Current limiter R2’s 330 Ω assumes a 5-V rail and a low impedance driver. ...
.. 1a's circuit without using additional compensation circuitry (Figure 2). For a 2400 bps serial link with less than 10% error on the bit length, the rise-time estimate is 42 µsec, which corresponds to a 7.5-kilohms resistor. ...
.. to drift from 1.25 V to 1.2375 V, causing the output current to decline by about 1% of full scale. This 1% corresponds to 10 mA out of 1000 mA and is somewhat less than 3 LSB of an 8-bit setting. That’s perhaps not great, but it’s ...
.. regulator chips. This scheme makes power-capable DACs with double-digit wattage outputs. For example, “0 V to -10 V, 1.5 A LM337 PWM power DAC” ( Ref. 1 ). The simple circuit in Figure 1 joins this favored family but makes ...