Stereo Preamplifier Circuit (741)

100 Mhz converter

The 2N4416 JFET will provide noise figures of less than 3 dB and power gain of greater than 20 dB. The JFET's outstanding low crossmodulation and low intermodulation distortion provides an ideal characteristic for an input stage. The output feeds into an LM171 used as a balanced mixer.

Courtesy-light-delay-switch

This circuit holds on the internal light for approximately one minute after the car doors are closed. When the door contacts open, a + VE pulse is applied to the base of Tl. This transistor turns on, turning off T2 and charging the 10-llF capacitor. T3 turns on, holding on the internal light.

Optically-int-erfaced-ring-detector

This ring detector, utilizing a neon-LDR (light dependent resistor) optocoupler, simplifies inter

Battery Charger

This high-performance charger quickly charges gelled lead-acid batteries, and turns off at full charge. At first, the charg

Variable Wein Bridge Oscillator Circuit

This circuit uses a single potentiometer to time a 300- to 3000-Hz range. A FET op amp is used at A1 and A2.

Rugged lamp driver

This circuit is capable of driving filament lamps of nominal rating 200 mA at 60 V dc from a CMOS logic signal. The lamp or load is connected in series with the Darlington transistor TR1 and emitter resistor R5. The Zener diode ZD1 establishes a soft reference voltage on the collector of the...

Light activated logic circuits

These circuits illustrate some of the common logic functions

Beam sputter for oscilloscope

The basis ofthe beam splitter is a 555 timer connected as an astable multivibrator. Signals at the two inputs are alternately displayed on the oscilloscope with a clear separation between them