nº937

Knight rider led effect with 20 leds, 1 BC transistor, supply 24V

nº936

8 leds, 1 bipolar transistor, supply 9V

nº935

Simple led chaser with progressive shortening, supply 2xNiMH

nº934

Simple QC2.0 - 12V mode tester for USB charger. Checks if USB charger is true QC2.0

nº933

Precise refrigerator temperature alarm. When internal temperature exceeds preset value between 0 and 10 degrees Celsius a powerfull alarm signal is triggered. It can be heard even with door closed. Low current consumption in stand-by, Supply 4xNiMH

nº932

Simple "red led catch game" with adjustable speed, supply 2xNiMH

nº931

SW band to MW band frequency converter with 1 transistor, supply 4xNiMH.

nº930

Ganged variable capacitor with reading scale

nº929

Simple lamp flasher controlled by LDR, supply +5V_USB

nº928

Four levels clapper for incandescent lamp; low sensitivity to speech, high sensitivity to clapping, supply 230Vac/50Hz.

nº927

Dimmer for incandescent lamp with 4 levels: OFF, L_min, L_med, L_max; tact-switch operates with total galvanic isolation, supply 230Vac/50Hz.

nº926

Staircase lamp controlled by smartphone ringtone. The ringtone audio signal derived from earphones output activates staircase lamp for the predefined timing. Complete galvanic isolation between TRS plug and circuit hot side is achieved by: 1) using one optocoupler to trigger monostable circuit and 2) A photovoltaic led coupler consisting on the hot side white led voltage regulator coupled to yellow led which supplies energy to the optocoupler audio trigger amplifier.

nº925

Light controlled audio spectral glider, supply 3V

nº924

Audio effect "wah wah", suppy 3V

nº923

Longwave experimental radio receiver with 2 bipolar transistors and loudspeaker output. Operating by night, tuning at 252kHz, Radio Algérie, Chaîne 3, supply 3V

nº922

Two RC resonant active filters select two frequencies: 910Hz and 2KHz.

nº921

Inductance meter 47uH-10mH; reading 1uH/ohm, supply 3V

nº920

Staircase timer opto-switch with about 18 seconds fixed timing, supply 230Vac/50Hz

nº919

Experimental SW(9MHz) regenerative receiver: 2 transistors, tickler coil, tuning capacitor, reaction capacitor, loudspeaker output, supply 9V

nº918

Emitter follower RC phase-shift oscillator

nº917

Beep beep mini alarm with led and 1 bipolar transistor supplied with 1 NiMH battery cell: the audio "joules thief"

nº916

Powerful alarm with 2 bipolar transistors is activated by separating small magnet from oscillator inducance, supply 2xLR03

nº915

Simple portable minimalist reflex radio receiver for MW with 2 bipolar transistors, only tuning control, loudspeaker output, supply 1,5V (1xLR03)

nº914

Led chaser with 18 yellow leds is controlled by single CD4017, 10 states counter, supply 3V

nº913

Simple Colpitts oscillator with MOSFET

nº912

MOSFET phase-lag oscillator

nº911

Bar with 3 mini incandescent bulbs, supply USB 5V

nº903

Simple astable multivibrator for RGB led, supply 2xLR03.

nº910

Slot machine with 2 RGB leds. Jackpot self-flashing RGB led is activated whenever color combination is either Red-Red, Green-Green or Blue-Blue, supply 3V

nº909

Blinking pair of incandescent light bulbs with 1 MOSFET, supply USB 5V.

nº908

Roulette with RGB led, supply 3V

nº907

Loop with 10 leds with variable timing controlled by self-flashing RGB led, supply 3V

nº906

MW radio receiver with 2 transistors, USB +5V supply voltage

nº905

Portable AM reflex radio receiver; only ferrite antenna; no ground connection; 2 bipolar transistors; loudspeaker output; supply 3V

nº904

Inductance meter 47uH-10mH for oscilloscope by impedance halving method, supply 3V

nº902

"Knight Rider" led effect with 1 bipolar transistor, supply 12V.

nº901

Simple analog multiplying circuit: PROD=M1xM2 with M1,M2 between 0,00 and 1,00; supply 9V.

nº900

Timing for the simple transistor astable multivibrator running in 2 possible modes.

nº899

Simple flashing controller for Christmas lights, supply 230Vac/50Hz.

nº898

Experimental TRF audion MW radio receiver: 1 transistor; loudspeaker output; about 10m wire antenna(and ferrite antenna) and PE connection. Receives during daylight MW Antena 1 with 630KHz carrier at about 30Km distance from transmitter; supply 24V.

nº897

Self-quenching oscillator with 1BJT, supply 2xNiMH.

nº896

Minimalist alarm siren: 1 resistor + 1 BJT + 1 blue led + 2 capacitors + 1 loudspeaker, supply 9V

nº895

Minimalist multivibrator for dual(red/green) led : 2 transistors + 1 trimmer potentiometer + 1 capacitor, supply 2xNiMH.

nº894

Simple voice changer with 4 transistors, supply 2xNiMH.