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.