Circuits & Schematics - 15

AC signals can emanate from many sources, and many of these sources are incompatible with the most popular interface voltages, such as TTL. A temptation always exists to capacitively couple the ac signals because capacitive coupling strips off the ...

Pulse width modulation (PWM) is a simple and inexpensive (therefore popular!) way to implement moderate performance (e.g., 8 bit resolution low speed) digital to analog conversion, but improvising cheap DACs isn’t the only thing PWM can do. ...

This Design Idea describes a simple way to form a reliable astable or monostable multivibrator from a set/reset latch. You may find it useful because it lets you minimize the number of standard digital ICs your design requires when absolute ...

No currently available V-F converter will accept bipolar (AC) inputs. This feature is desirable in power line monitoring and other applications. Figure 1’s V-F converter accepts 10 V inputs, producing a 0 kHz to 10 kHz output. Linearity is ...

Verifying the rise time limit of wideband test equipment setups is a difficult task. In particular, the “end-to-end” rise time of oscilloscope-probe combinations is often required to assure measurement integrity. Conceptually, a pulse ...

Circuit designs abound for linear triangle/sawtooth generators, and many are based on the iconic LMC555 CMOS analog timer. But relatively few are voltage controlled, making them tricky to program with a DAC, and most have unbuffered outputs that ...

Frequent contributor, Peter Demchenko, recently published “A safe adjustable regulator” ( Ref. 1 ) discussing the likelihood and consequences of rheostat-connected voltage trimmer failure in three-terminal adjustable regulator ( LM317 , ...

Figure 1’s circuit uses the LT1720 dual comparator in a 50% duty cycle crystal oscillator. Output frequencies of up to 10 MHz are practical. Figure 1. Crystal oscillator has complementary outputs and 50% duty cycle. A1’s feedback ...

Many industrial- and medical-system circuits require isolation from the mains-ac power. You can often send a signal across the isolation barrier using a small transformer; transformers do not pass low-frequency signals well. The circuit in this ...

Positive feedback is a typical technique for distributing hysteresis around a comparator, provided that you have a resistive path between the comparator's output and the noninverting input. Positive feedback forms two threshold voltages that ...