Electronics modules sourced China c 2014.
Very cheap, and useful to have in your spares compartment!

AUDIO AMPLIFIER

1. LM386 audio amplifier chip
2. 200 times voltage gain
gives 1 watt (max) output
3. On-board speaker wiring Block
4. On-board 10K variable resistor,
volume adjust
5. Onboard LED power indicator
6. Input audio signal via wire-wrap pins
7. Operating voltage: 5 ~ 12V
8. Board size 41mm x 13mm

www.ebay.com/itm/LM386-Audio-Amplifier-Module

VCO to 33MHz

1KHz to 33MHz Adjustable Square Wave Oscillator Module.
Design based on Linear Technology LTC1799 IC.

Datasheet LTC1799

ebay.com.au/itm/1KHz-to-33MHz-Adjustable-Oscillator

DC VOLTAGE BOOSTER

DC-DC Adjustable Step-up
boost Power Converter Module
XL6009 Replaces LM2577
Ringing choke type design
At max setting with a 3 volt Li cell as input I measured 20 volt O/P (nil load)

XL6009 DC-Convertor-Datasheet

ebay.com DC-DC-Adjustable-Step-up-boost-Power-Converter

LED DIGITAL CLOCK

LED Digital: Clock, Date, Voltage, Temperature display
Module size 40mm x 13mm
requires cr 927 mem backup cell

LED-Digital-Clock-Voltage-temp-Detector

Shown here fitted to my Satellite receiving antenna
Keep a check of the time for: A.O.S. time @ max elevation, L.O.S.

FM TRANSMITTER

FM transmitter module
(wireless microphone)
range 100 metres
freq range 85~115MHz
size 2cm x 1cm
current drain 9 mA
Aerial impedance 50 ohm
useful for audio surveillance

ebay.com.au/FM transmitter module